The only thing I would see them slowing you down is the soles aren't very flexible, hence why you don't get that much spring off of the shoes when running. (My opinion) you'll be fine man. Just practice your sprints
Cleats are recommended for almost any position that has a lot of field movement (a.k.a. all of them) It's not a matter of speed, cleats are so you don't slip and fall. Without cleats, lots of sports would just be people falling down.