Is there a way to write private comments or reviews?

This is just me being curious, but why would you want to do that...? Isn't the point of comments and reviews that other people should see them?

~4400 manga completed
~1700 ongoing...

I'm not OP, so I don't know for sure if this is what they mean, but perhaps they don't want to write up a full public review, but they'd like to have their own notes/reviews for personal use?

Bato has a notes section, and honestly at first I thought it was kind of dumb, but then I ended up using it all the time. I read a lot of series on their official platforms, but I love to have the ability to add links (like to MU for instance) and any notes reminding me of characters or telling me why I decided to drop a series all easy to find in one place for my swiss cheese brain.

Quote from KCL786

Is there a way to write private comments or reviews?

There is no way to do this right now, and we have no plans to add it

A just ruler amongst tyrants