I think we are talking about two different things here. I think bitcoin will gain investment initially as a store of value and not much else. The reason an endowment or pension fund would buy it would be the same reason they would buy gold... they want to own something that isn't correlated with other investments. Bitcoin right now is one of the best uncorrelated assets on the planet. There have already been models showing that the perfect risk adjusted portfolio has 4-6% exposure to bitcoin. That percentage can be increased or decreased as it relates to risk preferences, but it needs to be included for sure.

However... like you alluded to, over time there may be other coins that have more potential utility than just a store of value and those will certainly attract investment as they become apparent. Until then though, bitcoin will capture the lion's share of new institutional money.