The only way Goku beating Beerus is good is if Super is about to end. Otherwise, it's the equivalent to only lasting 10 seconds during sex before blowing your wad. And when you think about, that pretty much describes this entire tournament arc. Am gonna make a thread detailing a lengthy review of it when the arc finishes.
Goku will only defeat Beerus IF he *fully* masters UI. I say this because Whis' comments have heavily implied that, while Beerus has yet to completely master UI himself, he's very close -- closer than anyone else, in fact.
...That's what gave Beerus a huge advantage over the other universes' Hakaishin in the manga, for example.