Sorry, I feel bad right now.
Steemconnect signs transactions on their servers
Of course they don't store users private keys, we miss understood each other. Now I'm confused a little. I only know I didn't mean they have access to private keys, it would centralize network.

I tottally agree with second point, I don't know why I was so convinced they provide
only basic functionalities. I was happy about release and I didn't make proper investigation. Sorry.

I will edit my post to fix this.

Edit.
I removed this missleading parts. I wanted to show advantages of my solution, but I made it in wrong way.


Sorry.