They are completely different things; it’s hard to say if one is better than the other. Breaded Pork Tenderloins are blue-collar, mid-western food while Katau is exotically foreign, so it wins in the P.C. race.
Katsu is more of a breaded, boneless pork chop served with a dipping sauce. The meat in BPTs is usually pounded so thin not much of the pork flavor comes through.