Legality, schamaglity.
The EU, which also requires influencers disclose ad content, found 80% of influencers don't.
When influencers fail to properly label paid content, both the influencer and the brands they are promoting may be violating the law.
searchengineland.com
Again, influencers being paid to promote corporations is incredible normal.
Here's an example I saw recently on Instagram. This woman is not a Disney influencer, she's a beauty influencer, but Disney invited her to come experience the new ride and shill for it. No where on her post does it say this is an ad, but that's exactly what it is - opening date and all. Again, this is very normal corporate-influencer behavior.
It's just part of the marketing budget. No different than buying up billboard space or commercial time.