Time-Crunched Triathlete Training Program- Half Ironman?

I haven't followed the plan, but I do have the book and have read it.  My take on it was that even Carmichael was pretty clear in the book that using the plan for a half is somewhat of a stretch.  It should get you across the finish line, but was definitely too light to be competitive.

So, I'd say depending on your goals for the race, it could be an okay 'just finish' plan.  I wasn't overwhelmed by confidence, just in the tone in which it was presented in the book.

My own opinion - if you are a slower athlete (like I am!), these types of plans may not net enough mileage to have you feel comfortable at that distance.  Example:  The long run might be 1.5 hours (I don't remember, just making that up for example's sake).  A faster runner may complete 11 miles in that time - fine for HIM training.  But a slower runner might complete only 8 miles in that same time - probably not great for HIM training.  So keep that in mind fwiw.  You might have to add some time anyways to get your mileage where you need it.