uniseal vs. bulkhead for barrel containers

[SeeFu]

Why do people always recommend a uniseal vs. a bulkhead? I just found bulkheads that are made for barrels, wouldn't that be much better than a uniseal?

 

[mdb_talon]

Uniseal has always worked fine for me but this does look interesting. Seems it pretty much a standard bulkhead with a larger seal to conform. It may be worth a try next time i got curved surface.