I am wondering some ICO's accept only ETH. Some accepts BTC, ETH, LTC and other cryptocurrencies as well. Does accepting more currencies in ICO plays a roles in its success.
No. It's just their choice of what crypto to accept. I also see ICOs before that prefer to accept BNB.
Also Ethereum's smart contract are built for accepting only ETH. How other ICO's are accepting multiple cryptocurrencies and pays tokens accordingly? Do they have to maintain a sheet of who pays in what currencies in a sheet and allocate tokens accordingly. It seems to be a hard manual process.
They give a certain address for each investor and those addresses for each coin they prefer to pay has unique address.