Beginners are only allowed to leave notes on their own edits. While that might prevent spammers from sending spam to others via one method (did that ever occur? There was a report of spam edit notes in December 2011) this is rather user unfriendly. Also, the link provided with the explanation doesn't go to the relevant section. It goes to https://musicbrainz.org/doc/Editing_FAQ rather than https://musicbrainz.org/doc/Editing_FAQ#Why_can.27t_I_vote.3F. Which doesn't even mention yet that notes are affected too.

Take Edit #65258770 as an example. At the time they made that note they were still a beginner and I imagine they intended to leave a note on my edit but were forced to do it on their own edit instead. (See attached screenshot what my edit looks like to a beginner)

Directly messaging other editors is discouraged for editing relevant matters. As such beginners should be allowed make notes on all edits. Also, finding und using the contact form requires more steps.

If the goal is to prevent potential spam sent to editors beginners shouldn't be be allowed directly messaging other editors either which would be even more user unfriendly.

A feature was requested to opt out of direct messages completely.

Allowing beginners to make notes on all edits is also desirable because more and more edits were changed to be auto by default. There are already plenty long-time beginners with many auto-edits that are hindered from communicating properly with others.