My grandfather certainly believed in the beauty of Esperanto as a language, and was keen that there should be a native literature as well as plentiful translations from natural languages. But the two goals (utilitarian and fun/aesthetic) aren't really separate: he was well aware that there had to be a kind of literary critical mass behind a language, and a substantial body of past usage, for human beings to want to take it up seriously - and that for the same reason it had ideally to be not just simple to learn but also pleasurable to use.