yes, they can't rush due to their beautiful larger fins, and their nature to swim slow, I guess.. I never kept any betta. One of my friend kept him in hood-less tank and betta jumped out of the tank and died (my friend claimed that he died but I am guessing he was still alive when got jumped on the floor, it's just he was just socked and was playing dead during that incident! I told him before that these guys jump a lot, but who listens to me! LOL).
On other incident, I've had my first flowerhorn, my wife was treating him like "dolphin" to let him take food out of her hand, without hood on top, and he jumped outside all of sudden to catch the food, my wife screamed and I rushed to them, put that little fella back in the tank, he swam just fine without any issues, he stayed well, no injuries). I see some of our members keeping hood-less/uncovered tanks and I always think about that incident that FH can jump very high.. e.g. if there is any bug hovering at the top of the tank and FH sees him, he surely will try to catch that bug for food (or for fun!, these are little crazy guys)
)
Anyway, yes, every creature on earth likes larger space to survive, however those beautiful bettas do sacrifice a lot, and that's, I guess, because of those LFS put them into the containers. They have to put them in small container because they can not afford to have each betta on separate tanks.. They are fighter fish.! LOL..
BTW, nice to know that someone kept a betta in 55G, it's really nice of you. Well, IMO, 20 gallon single betta would do best, as we can use sponge filter and some BIO media in a bag, and a heater, he will be happy living fish on the earth I believe..