Fair points. Most Blockland servers revolve around explosives and jumping around like a maniac. I should mention, though, that you can still walk while using the SD. Also, if you stutter step like it's counter strike, it works really well in normal gunfights. However, being knocked around past walking velocity (i.e. bullet impact) will ruin it. You also can't use it in a moving vehicle.
It's still incredibly niche, yes, but all the more power to people who make CQC maps without a lot of explosives. It can be handicappedly overpowered when you have the jump on someone, even on multiple people.