Not really, you would then need double the ignition components. So for each engine (2 cylinder) you would need 2. Your boat...would need 4 of everything. It's firing on the exhaust stroke so it's not hurting anything.
My old Skidoo snowmobile is a 2 cylinder fan cooled engine. It has 2 sets of points in the housing, 2 condensers, and 2 coils mounted to the outside of the engine. Would be cleaner and easier with just one. Adjusting those points can suck when you need to do it.