this idea doesn't sound good at all to me.
i like investing in bitcoin and holding it and i even like spending some bitcoin as online payment but as all my salary in form of bitcoin no it is not a good idea.
I think you better quit your sig campaign because it is not following your belief and thought on being paid fully in bitcoin. Since you are indirectly saying that your campaign mode of payment is a bad idea. Anyway, as long as the terms are good I don't mind being paid in bitcoin. This bitcoin participation gives me another set of potential earning because only a few people out of the whole population knew about bitcoin and the opportunity it gives.
if you want to just get paid a portion of your earnings in bitcoin, because all is not practical then signature campaign is a nice way to earn some btc and don't have to exchange.