There are now more transactions done on the Ethereum network than on the bitcoin network. No company can ignore that, especially as Ether seems to be developing all sorts of applications and layers on top of it.
Ethereum has a massive user base, which is why it is a smart move from blockchain to add Ethereum, but I strongly believe that its popularity as it is right now, won't last endlessly. People are going nuts on Ethereum because of the massive amount of ICO's, where hundreds of thousands of coins get locked in. I am sure that if there was no ICO hype, Ethereum would still be an average altcoin.