There is also a difference between “walking the lines” and being able to get the step. I did the 3ft as a junior on a 15.1h TB who had a very average step, at local rated shows. He did not walk the lines. With a forward canter carrying appropriate pace (and I don’t mean running down the lines) we were always fine.
Will most horses just shy of 15.2h walk the lines in the 3ft? No. But many horses in general don’t. Most horses can, however, get down the 3ft lines fines on a nice normal canter pace. I echo @supershorty628 - this isn’t a big ask, especially at the local level where the jumps are probably going to be closer to 2’9’’.
My current horse is 16.2 with natural 13/14 ft step, but his first time schooling down a line before he wakes up and gets moving he does the add nicely. By the third time I’m praying we’re not leaving it out. It may be something you have to think about with pace and track (riding straight down the line), but unless this specific horse had an unusually short stride, that height would not concern me for a rider whose goals are the 3ft hunters locally.
Personally, I’d rather have a horse where I can jump into a line and nicely move up than land and have to pull the whole way down to fit it in. Too big of a stride has its own issues…pick your poison.