Mixamo still has a huuuuuuge audience which is super cool to see. Here's a better description - (confusingly placed under the Fuse support area) The only thing you can't do with Mixamo content is re-sell it as-is, essentially competing with Mixamo with it's own content, it has to be used in your project. The content license is very open, and all Mixamo content is free for commercial or non-commercial use. You will also never have an issue after your game is finished. There's no package deal though, you don't need any subscriptions to use Mixamo, just a free account. At the time there wasn't much in the CC ecosystem which could take advantage of Mixamo other than Photoshop and maybe AfterEffects, so continuing to make the animation library broadly available was a bit of an olive branch to the gamedev community, and freeing it up aligned with our goal of democratizing animation and indie game development. What they had to gain was good will- Mixamo had historically been a gamedev focused company but we also definitely had customers in simulation, VFX (looking at you Terminator: Dark Fate), design, etc. We were focused on getting Fuse integrated with Creative Cloud back in 2015 and it took up all of our bandwidth.
Mixamo was actually completely paid before Adobe acquired us, it was Adobe's decision to make it free.
