Conditional +1, the condition being that this only works on IRCds that support a form of TBAN or timed ban. The IRCd has already accepted the additional overhead, so let the ircd deal with it.
Otherwise I'd say no, it's not worth services keeping track of all the timers and callbacks when a client bot can handle this and keep the overhead off services. Yes, this is a popular feature in Eggdrop, but Eggdrops normally only monitor 1 or a few channels and not the entire network.