Hi,
I am new to this and have a fundamental question: Why do ICOs ask us to send ETH using myetherwallet?
Why can't I send them directly from kraken.com?
Thanks in advance
Because the ethereum wallets other than myetherwallet.com doesn't support Erc20 tokens and it is must to contribute your ether from the wallet you are sure for its Erc20 token support.
If you send from exchanges like kraken,bittrex, the ICO developers will send tokens to your address but you will not be able to see those tokens.
Myetherwallet can hold all erc20 tokens and ether as well. So, it's compulsory to use MEW while you buy any tokens