Exactly. I get it. I know it would be a major privacy leak, but wouldn't it be more convenient to provide the xpub?

Once you spend from an address its security is weakened. They are requiring unsafe practices. 

grege

Thanks. I know it would be a major privacy leak, but wouldn't it be more convenient to provide the xpub?

> What's that thing called? Isn't there a Bitcoin wallet key that just lets you see all your addresses?

xpub

This is all a mess, and they're just making it worse. If you don't reuse addresses, you're in trouble unless you consolidate transactions before sending to the exchange. What's that thing called? Isn't there a Bitcoin wallet key that just lets you see all your addresses?