No the real reason is: you can still w.nk yourself with the idea! (pardon my French) without the pain of taking care/answering real, demanding, not getting it, or plain indifferent (non)users. Until you have launched for real, you can dream of your beloved app/API/novel/idea/etc, that it will be so great, so new, so cool, everybody's going to be blown away and come to it in flocks. You can still dream in the Limbo. Once it's out ... the hard indifferent reality sets in. (Until that hockey stick curve of course ;)