Upshifting without clutch.

I've talked to a few people about this and they don't use their clutch because it shortens shift time. My question is this. Can this hurt your clutch at all? I know there are systems out there that will kill the fuel to the engine and allow for a quick shift but I still don't know if this could put any extra strain on moving parts.

 

Ok, thanks. Cleared up a few things.