Puffing yourself up doesn't necessarily translate to power. Conor already lacks power outside of FW - making himself slower is both going to make him easier to avoid and make the shots that do land less impactful. That's not to mention the reach disadvantage that he'll have against opponents in higher divisions.
Plus, the dumbass already gasses out in every fight, lol. How's he going to go for more than three minutes when he's actively burdening his gas tank with non-functional weight?
The next Conor we see is probably going to be the worst Conor we've seen.