this is upsetting. I don't use the remote app regularly but for setting up accounts for streaming services it is really helpful to have that keyboard on your phone.
I doubt Tim referenced the ATV4 that didn't exist. As far as anyone can make out, BT keyboards don't work, the Remote App doesn't work, and there are no plans to do anything to correct that. Part of the new platform experience.
Hopefully we can get a better way to set things up, especially Apple ID passwords and others where we might have a real password.