It's their availability that makes them good tames. They're found all over the place, have poor torpor tolerance, and are quick tames. You can quickly and easily build a huge legion of these guys to take on virtually anything. My pack of around 10-12 once shred a wild rex in seconds. Its corpse didn't even get to hit the ground. They're expendable but fast and strong, a perfect footsoldier.
The raptor is a good beginning mount.It is good at gathering meat and is fast. The raptor however has low stamina and health so fight smaller dinosaur to level up and then move on to fight larger dino. The raptor is a pack animal and in a group can easily kill players. It is also good at base defense if you put your raptors on aggressive and wander IN YOUR BASE WALLS. They are a good first mount and even helpful later on when you tame multiple and make a pack
Generally, you're going to want to invest in stamina and carrying weight for a while if you tame a low-level raptor. They're naturally fast,so you don't truly need many points in movement speed, and you can outrun almost all other predators, so health isn't needed either.