Any one can answer my question?
yes indeed, most ICO always need an ethereum address to make a payment. but there are also some ICOs that accept the wallet address other than ethereum. it all depends on the ICO rules.
Not dpeend on the ICO rules but depend on whether the ICO plan to use ethereum smart contract, waves', or making their own blockchain. especially a coin that's independent from bitcoin or eth or waves by creating their own blockchain often accept so many altcoin as their payment method, not relying to the smart contract only.