Honestly, that doesn't sound bad, as long as it's clearly communicated and has opt-in/opt-out.
I wouldn't mind selling some of my data that i choose consensually, and getting fairly compensated for it.
Especially when comparing that to how most (if not all) current major companies just covertly steal all they can about you and sell it behind our backs to whoever.
Saying all that, i don't support current AI model training practices at all. So i agree (for now) with the means, not the end results.
Probably same reason cancer always needs to grow. It's a fundamentally broken part of the system.