In UU he's used a fair amount actually.
Thanks to his herbivore ability, he's commonly seen as a check to sun teams that go for chlorophyll abuse. His high attack can be used well as a sweeper as you said. He also sees some use in OU as a check to Serperior and his leaf storm ability.
His main downside is his substandard speed, which, even with his high HP, tends to be his downfall. He has nice defenses, but he won't always get the chance to hit first, so the damage coming from them as well as reckless recoil damage can really add up quickly and knock him out. He's powerful with recoil moves, but they obviously kill him off quickly.
