Just replying to myself.
Adding server-start would be a friendly update to the user manual – @marcos Would you be willing to create a PR for it?
(server-start)
(require 'org-roam-protocol)
It looks like it might have worked if -nw was added (to open the daemoned Emacs session to open in the Terminal – it may require the Terminal to be already open. Can’t tell without a Mac machine).
Or -c option added to create a new frame.
Basically, daemon has been working as an Emacs server quietly in the background without a new frame to interact with the user… So the Stack Exchange response is not entirely correct. You cannot start daemon without an emacs server, because daemon always starts an emacs server. But you can turn it off, which renders daemon useless as the post says.
on open location this_URL
set EC to "/opt/homebrew/bin/emacsclient -c --no-wait "
set filePath to quoted form of this_URL
do shell script EC & filePath
tell application "Emacs" to activate
end open location
The daemoned Emacs does not seem to create a new frame automatically through the protocol. So it looks like adding server-start in the init for the usual Emacs session would be the easiest way…