I never put any bottom paint on my plywood dinghy which stays in the water as long as my sailboat. It gets a coat of plain enamel each spring.
I only notice slime and algae about mid August and drag it up on the dock and take a brush to the bottom(isn't that what some on this thread are doing as well?). By haul out, the slime and algae are about the same. No barnacles though.
I wouldn't mind a neutral effect, but I'd hate to find out bottom paint grows barnacles.