sure, a delayer could be good without their lag if they learn how to spar without it. if they didn't lag and played with their current strategies (run away for the whole spar and swing randomly and pray that it hits), then no. do this in a match between two people with decent connection and tell me how it works for you compared to how it works for someone with bad connection. let's not pretend delayers have any sparring skill at all with their current strategies here please.

sidenote: this doesn't apply to all delayers, some (probably only shiden, maybe shan) actually have the ability to leave their god, the wall, and spar offensively.