tl;dr
Why try and make Bitcoin do everything instead of having an ecosystem of specialized currencies?
Nobody is in control so thats why we get a ton of alts created. As regards BTC i think its good to have many options with the currency, you dont have to use them. It has more value because it has potential to do so much in the future.
Blockchain technology makes innovation in several sectors. So based on the same technology several ICO projects evolve around and this in turn gets value and moves into circulation as a store of value. These day countries try to make their own fiat get digital form. This too is an reason for the existence of lots of digital currencies.