Hi, im curios about the following:

"Ethereum Payment Instructions

If you’re using ETH to purchase, you will need to first move your ETH to your MEW wallet address and then send your ETH to us from that MEW wallet address."

Ist there a reason why i have to use an online service to participate the sale? The official ether wallet should work aswell, shouldnt it?
I hate having private keys shared online, even if it is an open source project like MEW.

Can you enlighten me?