Is surfing in competitive matches useful?
On the contrary, I find that surfing helps a lot to improve skills. Personally, it's an extra workout for me.
Purely theoretically, surfing is not particularly useful in competitive matches, and cacers often think that playing on such servers entertains players, but certainly does not help them become better at the game. That's not entirely true. Yes, you can't glide through textures on main mappool maps in the same way as you can on specially honed locations, but surfing helps a lot in honing your movements. With regular practice on surf servers, which you can choose here, you will move around the map more deliberately and clearly, as surfing teaches you that every extra move can be fatal.