One issue with saving a Discover Weekly list to Spotify is that Discover Weekly is generated based on the content in the user's playlists. If you add a bunch of Discover Weekly lists that are 28/30 duds you're going to start reinforcing the system to generate crappy lists.
I think that's why Spotify doesn't allow saving them. They do allow saving of the topical Discover Daily, which reinforces my belief here.
Just thought I'd let you know about the possible issue with your product. Even though I absolutely love it and would use it.
It's a relatively simple graph-transform that is just using occurence in playlists tor generation. Which makes adding the playlists self-reinforcing, which could have negative situations.
I have a wide range of musical taste, but a low number of playlists and can drastically change from metal to dance to hip-hop by adding a prebuilt playlist week to week.
Here is an article on how it works, and there have been discussions from the staff elsewhere on why DW is so good.
http://qz.com/571007/the-magic-that-makes-spotifys-discover-...
* https://standardresume.co/ - Started because I couldn't find a resume that I liked.
* https://amplitudeapp.com/ - A more advanced artist radio style playlist maker.
* http://rediscover.rile.yt/ - Automatically save Spotify discover weekly playlists.