I guess it is meant to be a bit of fun, creating a sense of a countdown to the "big day". A few people might go back and check each day, but I suppose most will just catch a few days on social media (they do a post every day saying saying what the new window reveal is), or just check back on January 1st, which is public domain day, and when all windows will have been revealed. They do a blogpost on that day too which unrolls the whole selection of highlights. E.g. see this one from PD day of this year: https://publicdomainreview.org/blog/2024/01/public-domain-da.... That's maybe seen as the main thing.

I see they have updated the post now, showing English translations for all the images. The "erdapfel" one is now displaying as "Possibly watermelon or cucumber": https://publicdomainreview.org/collection/hartlieb-book-of-h...