When paired with defense curl, rollout has extremely high power, however only after 5 turns. It would be very easy to counter it with (Sleep, paralysis, etc.).
No
When using Rollout it locks you in so you can't go for any other attack making you vulnerable and it has that 10% chance of missing, I would recommend just going for a psychical or special sweeper with stat boosting moves and then a good moveset.
Hopefully, this helps :)