In your opinion. If the tank is a reef ready tank it is certainly easier just to use a sump than to plug the holes and go with a canister. If the option is a hang on overflow I'd scrap it and go with a canister for sure.
Not sure why you think a sump is a waste of money on a FW
tank. It's a big customizable filter with tons of room for bio media and mechanical media IMO
, not to mention the added water volume, however slight, is never a bad thing.