While Monero makes some sense there, I don't see why would anybody use Ethereum instead of Bitcoin.
Keep in mind that most have cash and would have to buy Bitcoin, then exchange to Ethereum ... I don't see the benefit in that.
Because of bitcoin's problems of late, (transaction times, fees, hardfork uncertainty) they had to look for alternatives. So ethereum is the best option because it has liquidity and the closest one to implement mass scaling and also privacy. Monero has privacy ( not sure how good it is ) but it won't either scale nor will increase much in value / be very liquid.