This post is now outdated; beta 2 fixes this.
The recent beta release of TypeStatus for Mac has an issue that prevents it from showing a welcome message when you install it. That message contained a check box to tell TypeStatus that Obsidian Menu Bar is installed.
If you want to fix that, launch the Terminal app (it’s inside the Utilities folder in Applications) and paste this in:
/usr/libexec/PlistBuddy -c "Add Inverted bool true" ~/Library/Containers/com.apple.iChat/Data/Library/Preferences/ws.hbang.typestatusmac.plist
Then quit and re-open Messages.