Would it be a clever idea just sitting on ETH and wait for it grow if you are lazy and not like to take risks?
You are right.
How does this help ETH ? What do you think EOS is going to do with all the ETH they collect ? Why do you think ETH is so volatile right now ? Because all these ICO's are dumping it to get fiat or BTC to spend for their development.
BTW EOS is great tech and Dan is brilliant. He created Java Script and is a true Anarcapitalist that believes in the non agression principle. Bitshares and Steem are tech that is unmatched.
Now at the same time people throwing stupid amounts of money at this, like the yunbi investors, is just flat out stupid. Blame all the non educated crypto investors who used to be able to make money by investing in anything