If you don't use your brakes and just regen all the time, you run the risk of having your brakes rust.
https://nrsbrakes.com/blogs/supporting-articles/the-unused-b...
iirc some OEMs will automatically apply the brakes lightly during regular driving from time to time to counteract this
Yes, you are encouraged to slam on your brakes at least once a month to get the rust off. I live on the west coast (rain but low humidity and hardly any snow), so its less of an issue.