Both ETH and BTC have huge fees from time to time and I can't in good faith recommend them to anyone.
That was when the network was overloaded, as of current I believe it takes about $0.1cent +/- to excute a transaction on the ethereum blockchain and as of bitcoin I haven't done transact for quite some time but i believe the fees will be in cents too. We have various cryptocurrency so if bitcoin fees becomes high a merchant can have other options for the main time. I believe the goals is to get cryptocurrency adopted with bitcoin plotting the adoption.