The 10 holes came about because we found 10 we liked in the area we were given to work with. Paul Schock also made it clear he loved the idea of something different and encouraged a non-traditional number of holes.
I haven't played it yet, or the many variations on H-O-R-S-E that could be possible, but the number of holes may end up helping if people play a true game of H-O-R-S-E. Because the course can be played any number of ways:
-As a traditional par-3 course with a recommended tee location set by the superintendent each day.
-Or as a Mark described where the person with the honor selects the location for teeing off (and maybe even determines club selection if you really want to make it interesting)
-Or under some sort of variation on H-O-R-S-E where the honoree determines tee location, club selection, and a letter going to the low score on the hole, with the first person in your group spelling out HORSE winning. (Several holes also allow for a "bank shot" so some people might even call shots that have to be played).
-There is also a four hole loop where you can play with only a putter.
I'm sure people will create their own games, which will be the real fun.