Breeding a high level compy army is a waste of your time so taming a metric f*ck ton is the way to go. Riding a slower animal while surrounded by your army feels pretty awesome and it's hilarious to whistle attack target on whatever irritates you.
Everytime another compy comes near another, they get a boost. You can see the "+1, +3" etc etc. If you tame a bunch of these and put them in your house they're good for distracting players if you also have dimorphodons or onyc inside too
When it comes to the actual utilitarian use these things are good for about three things scaring noobs on the beach as you roll up with 20 following behind you or, egg layers which produces kibble for the pelagornis. The last is a special attribute of all shoulder ridden dinos, all the weight the compy carries is reduce by 1/2 when shouldered.
They do gain a squadron boost so having many of them is very useful, they are only tamable using prime meat for some odd reason, having tons in an air locked base on aggressive will for sure do some decent damage,