Incineroar is really good in Doubles, but not so much in Singles. Intimidate is really broken in Doubles (which is why you often get VGC teams with multiple Intimidate users), it can pivot with U-Turn and come in and Intimidate again to destroy Physical sweepers, and Fake Out is really good utility since you can still do something else with your other Pokémon, plus 115 Atk isn't too shabby, so it offers an offensive presence as well, which goes a long way when supporting and being supported by other Pokémon in Doubles.
However, in singles, Incineroar doesn't stand as well by itself. Intimidate is still good, but not as overwhelming as in Doubles, and Fake Out is a pretty mediocre option since you can't do anything else that turn. Its bad 60 speed in particular holds it back, limiting its sweeping options, and without being able to Intimidate spam as effectively, its 95/90/90 defenses, while not bad, don't hold up well enough to be a tank.
