Not sure on Discord Library, but with Steam that is configuration and I can't uninstall the game and then install it again later from within Steam.
What would make me be a fan of being agnostic would take something similar to Movies Anywhere, where if I buy a movie on Vudu and it automatically shows up in my Movies Anywhere "library" or more tangibly, in my iTunes, Microsoft Movies & TV, and Play Movies libraries.
Prior to Disney Movies Anywhere, I would forego the deals on Vudu due to being yet another library to manage. After DMA, I started to buy Disney/Marvel/Pixar movies where the best deal was at. After Movies Anywhere, that expanded to titles that were part of Movies Anywhere.
Many of these have existed; I remember using The All-Seeing Eye and XFire. But the integration with stores is what makes these new launchers like Steam and UPlay valuable to game publishers.
What would make me be a fan of being agnostic would take something similar to Movies Anywhere, where if I buy a movie on Vudu and it automatically shows up in my Movies Anywhere "library" or more tangibly, in my iTunes, Microsoft Movies & TV, and Play Movies libraries.
Prior to Disney Movies Anywhere, I would forego the deals on Vudu due to being yet another library to manage. After DMA, I started to buy Disney/Marvel/Pixar movies where the best deal was at. After Movies Anywhere, that expanded to titles that were part of Movies Anywhere.