You can still use some exchange services (send bitcoin and send ETH to the address you specified) or withdraw from the exchange. But pay attention to ICOs sending the token to the address you send.
There are wallets connected like a wave, and I think they also use erc20. You can keep your wallet safe and provide enough ethereum for the gas.
 ICOs do not require the address of etherium to essentially have their own blockchain and become altcoins instead of blockchain properties, they need to check their mainnet and more