I disagree about the main reason for wanting them. They may have been created to solve inheritance issues, but based on how often I'm asked about how to create private and read-only attributes, that seems to be the primary reason many people would want inside-out objects.
I'm reluctant to address the more esoteric concerns (like subclassing issues) in a primer -- the goal of a primer is to get someone started using a particular skill or technique, and it should not assume too advanced a prerequisite.
Besides that, your characterization that I'm "mostly concerned with" the private/read-only capabilities is ridiculous: I mention that issue once in the introduction, and refer to it obliquely once more in discussing class design. However, that latter is necessary because Class::InsideOut does require the developer to consider whether one's attributes are public, private, or read-only.
You are, of course, entitled to your opinions, but that doesn't make mine wrong.
Ramblings and references
The Code that can be seen is not the true Code
I haven't found a problem yet that can't be solved by a well-placed trebuchet