The thing with tokens is that because Ethereum is so young, the companies being built on top of it are by default super early stage, with no real traction or product market fit to show. So anyone buying tokens at this stage because they want a shared revenue stream of the companies profits, is making very risky bets which have a high likelihood of failure (on average).
I think it's the lure of secondary markets for DAOs that is behind a lot of the interest in, at least, The DAO - people buy the tokens early because there is anticipation of the token prices going up relatively soon after the crowdsale, fear of missing out etc.
I think a lot of it is driven by speculative motives rather than long term investment in Ethereum companies themselves.