I ve been testing some more and it's working fine.
I assume there is just an issue because you were previously logged in via SteemConnect.
Please logout, refresh the page and clear the cache (shift + f5) and login again via SC. You are in no way forced to use Keychain.
If you encountered an issue for a particular feature, please let me know which one.
RE: SteemPlus 3.8 : Full Keychain Integration