Martial arts in dragon ball is nothing but a meme.
From the very beggining we had Roshi training Goku and Kuririn but not teaching them anything about how to actually fight, or any new techniques, or anything. All that his training did was give them both superhuman strength. The rest they had to scramble and learn to do y themselves. Also, the very first tournament had very little in the way of actual fighting and was chock full of gags from beggining to end.
It has been like that from the very start. What MAKES DB DB is the fact that one side has a bigger PL number and is guaranteed to win as long as they don't fuck it up. From time to time a character such as Buu will have magic shit too but that's rare and even then it can be overcome with a big enough PL discrepancy (see: candy Vegetto)
This is why Roshi's fanservice episode was bad. It threw all that out of the window and made the audience question why didn't actual combat skills ever matter before in the whole series, when ALL it takes for one side is for them to have a bigger PL number for them to completely see through their foe's movements and be able to outspeed, overpower and beat them into submission while avoiding their blows like nothing (or even tanking them without any pain)