Amazon Photos offers unlimited original file storage for Prime members -- do they use this to train their internal AI systems or any other issues with privacy to consider?

Hi, I want to have an offsite backup for family photos. Cloud storage can be pricy. Upon research Amazon Photos seems to have a too good to be true pricing model of free unlimited original quality storage for your photos. Are they doing something with this data to help pay for the infra costs or is this really just bundled in with your Prime fees? Anyone have an idea? Thanks.

ai amazon privacy storage systems train