Single player uses:

1. Boss fight dino: Yutyrannus has a roar ability which makes your tamed dinos stronger, of course you should ride one into battle.

2. Pest deterrent: Set your Yutyrannus to aggressive and turret mode and it'll roar to scare off most dinos, though some such as a rex will become angry and attack instead but your Yutyrannus would probably kill them anyway.

3. Taming assistant: Since the yuty's roar causes dinos to panic and try flee, you can use one to prevent wild dinos from attacking if you're trying to KO them.

4. Meat gatherer: Yutyrannus is one of the best meat gatherers in the game, second to the rex and third to giga and carchar (who are equal).