Hi @wehmoen, thanks for your comment.
I also posted a workaround here if you're interested: https://steemit.com/utopian-io/@blockchainstudio/steemconnect-login-with-posting-key-instead-of-active-key
Eventually, unless app requires background work(autovote, scheduled post), steem keychain is the right way. Unless SC3 provides something very cool, it'll be quickly replaced by keychain. Thanks!