MailStore --- anyone using this program?

[Jester]

I wanted to make a backup of all emails to my local drive for a Google Workspace account (gmail). I tried both the google Workspace export as well as Google takeout and both simply don't work on my Win 7 PC.

I then created a new gmail account and imported from the Workspace account and that worked seamlessly, however I'm still at the mercy of google.

I tried Gmvault to make a local copy, but Google blocks that program. Next I tried the tool MailStore that archives and exports email accounts and it worked quickly and seamlessly. While in the mailStore GUI I can see all my emails, however the file size of the local folder that they are stored in is only 65MB vs. 5GB that Google claims to be using to store the emails. Yesterday I deleted about 4000 old emails (1000 remaining) and this reduced the Google claimed space from 13GB to 5GB.

What I'm trying to determine is: Does gmail save email in such an inefficient fashion as to consume massive amounts storage space (5GB vs. 65MB)?