Smaller shows tend to just have large distributors, manufacturers and such, meaning that many startups, foreign companies like Chinese companies do not attend smaller shows. The reason is ROI. Small companies or a foreign companies, the cost of travel may not justify the lower attendance. So if you mostly work with the larger companies, it won't make a difference. They are also in smaller venues, so it seems just as crowded, but maybe 1/4 the people of ISC West.
I like to compare it to a auto show. When you go to a small town auto show, you see all the latest cars all the major companies offer. When you go to a premier car show like the Los Angeles or Detroit Auto Show, you see more manufacturers, more products, products about to be released, future concept cars, better looking booth babes, higher production values, just an overall a better experience. I live in a small county in So Cal of a smidge over 3m people and trust me, we don't rate any better than a town with 3,000 people, I have to make the trek to L.A. to see the good car show, LOL.