Solves a different problem. You can't trivially automate takeout. What if I just want an offline record of my emails for the day that google decides to delete me from the internet?
Well this is what just a normal email client does - it downloads latest emails via IMAP.
That's why imap-backup is useful.
Lol that’s an email client! Not all email clients have a manual UI.
I'm confused -- Mbox files can indeed be viewed offline.
(Not to say your point about the ease of automating Takeout is not valid.)