They are two components of making every team the in world story and out of (real) world reasons. I don't care to overthink it. They put together a team that can sell books as the flagship.
Rogue is versatile enough to exist with Synch and visa versa. Heck I am excited to see Synch used as tracker his aura gives him the ability to find superhumans and beware if they are trying to sneak up on them. If more creative applications like that appear because they are trying to be different I will be happy.