Watching all the floatplanes coming in and out of Vancouver harbour a couple of years ago is one (out of many) of the motivations for getting my PPL. It looks fantastic fun, and once I've finished the PPL and got a bit more experience I definitely intend to get some seaplane flying in (either in Scotland or British Columbia).
As for FFF's point about how many places can you use the rating in the UK - I don't know - does anybody know? Can you simply drop in on Windemere or Rutland water etc.? I am guessing not !!!
Mr.W