The long answer is a little more complicated, but only because the ego loves to hear itself think.
Nancy and I came across A Course in Miracles over twenty years ago, and I count it among a half dozen or so Divine Devices put in my Way by the Teacher about which I can rightly say "it changed everything". (Here, I use the first person pronoun not to exclude Nancy, but rather to avoid putting words in her mouth, as she and I see A Course in Miracles slightly, although only slightly, differently.)
As you very well know, Elsa, like all True Teaching Instruments, A Course in Miracles is ultimately about Self-Realization. That is, its focus and function are about realizing who and what we are (and are not) in Truth. In that sense, A Course in Miracles is irrational. It is not intended for the rational and separative-thinking mind, and therefore it is not, and cannot be, understood, and neither is it intended to be understood, by the rational mind.
Again, like all True Teaching Instruments, A Course in Miracles is precisely and beautifully designed to transcend the egoic mind, and thereby to transport the serious seeker beyond the limits and fetters (illusions) of the mind. That's what it is for, and, properly undertaken, that's what it does. Therefore, in my view and personal experience, A Course in Miracles truly is a course in miracles.
I suggest to seekers coming to A Course in Miracles for the first time, that they set aside the "Text" and the "Manual for Teachers" for six months, and devote themselves solely and privately (that is, not in the context of a group) to the daily exercises presented by the "Workbook for Students," which I urge them to do every day precisely as directed, with enthusiasm, joy, and every expectation of success, and without trying to decipher or understand them, or in any other way to consider their merits. In a word, do the daily exercises just as if they had been prescribed by a trusted and beloved physician.
Why eschew groups? As I read it, A Course in Miracles is not a group activity. Rather, A Course in Miracles is written for and addressed to a singular seeker. In this sense, A Course in Miracles offers the serious seeker a traditional Guru/disciple relationship. That is, a relationship between the student and what A Course in Miracles calls the Holy Spirit.
Here, the Holy Spirit is the Guru; the seeker is the disciple. This intensely intimate, sacred relationship is fundamental to A Course in Miracles, and essential to its successful application. It is real, even every bit as real as if the Teacher were flesh-and-blood. And it is powerful. Indeed, it is the answer to the question asked by so many students of A Course in Miracles: Do I need a Teacher or a Guru? Properly undertaken, A Course in Miracles provides the seeker with a Teacher or Guru.
But, like the Guru/disciple or Teacher/disciple relationship in all traditions, this one is One-on-one. The seeker, alone and not as a group activity, personally and privately surrenders to the Guru, initially by faithfully and unconditionally obeying the instructions presented in the Workbook for Students. And the Guru, alone and not in a group, gives Himself or Herself wholly to the seeker. In a very real sense (ultimately, in the only sense that is real), the two become One.
In all spiritual traditions I know of, as well as here, the instructions and guidance given to a disciple by a Guru or a Teacher are private and secret. Further, the confessions by a seeker to the Guru or Teacher are private and secret. None of that is fit material to be debated or dissected among the other students or disciples of the Guru or Teacher. To be sure, these very debates, discussions, and dissections take place nonetheless among the disciples or devotees in all spiritual communities or ashrams, and undoubtedly always have, just as in fact they take place within the community of A Course in Miracles students today. But, all the same, I urge serious seekers to recognize, at least in the beginning, that they are fundamentally a waste of time and energy, or worse, distracting and confusing.
Please understand, Elsa, that none of the foregoing is intended to suggest that groups do not serve a valid and useful purpose, for obviously they do. In virtually all spiritual traditions, seekers are urged to seek like company, other seekers like themselves, from whom they can receive encouragement, nourishment, and reinforcement. We all need some of that a lot of the time, and others following the same or a similar path can provide it wonderfully. To hear a friend say, "Yes, I recognize that obstacle, I tripped over it, too" can be extraordinarily reassuring. But that is very different from providing the egoic mind a forum in which to rationalize what is fundamentally irrational, and what, if it is to do its wondrous thing, must remain fundamentally beyond the grasp of the rational mind.
So, again, for six months at least (or until the medicine has had a chance to take), I recommend that students of A Course in Miracles avoid any activity that gives the egoic mind an opportunity to claim the process for itself, and thereby covertly to transform A Course in Miracles into just another set of marginally helpful self-help books, which the egoic mind, feeling threatened (and rightly so), will desperately try to do.
For those students who are willing or able to do that, I am convinced A Course in Miracles will prove to be truly miraculous.
Anyway, that's the long answer.