It may be a bit different, but there's still plenty of potential for people to donate and not be happy that their donation is forwarded to a third party Jellyfin Android if they personally have no interest in the existence of Jellyfin Android.

(I also agree with various other reasons in other people's comments, most of all that this lets donors vote with their money on which third party projects that work on top of Jellyfin get the money, rather than Jellyfin having to decide which ones deserve what proportion of spare money.)