Are you sure? They do obscure the direct download links on the German kobo site (kobobooks.de), apparently preferring people to use their e-readers sync functionality. But last i checked I was able to download the kepub files after some browsing around in the web interface. I can't verify this now as the site isn't loading for some reason
Replying to myself here. it is indeed possible. On the website, go to "My account -> my books" (for me that's https://www.kobo.com/de/en/library) where you see all the covers of your books. Directly underneath the cover are three dots "...". Clicking on them brings up a small menu with a download option.
But now that I think about it, it might also have sth to do with the fact that coincidentally, all the books I bought on Kobo seem to be without DRM (publisher is Tor.com), so maybe that's got sth to do with it as well.
