Foxhound5366
Honorary Master
It's more about the matchmaking experience, as wolf said. At your rank, being matched against people of Wolf's rank just isn't fun. You don't really learn anything, you're just dead. Not a criticism, just a statement. That's why we rather play against people in a similar skill group, so you can also win, learn and develop skills and confidence.
Also, most people do warm up with casual or deathmatch before playing comps.
But precisely! So it makes no diff, if anything you may end up being matched with even tougher enemies in casual, if they're just there to warm up. At least in comp I know I'll be matched with players like you guys, but in casual it's anything goes.