I built an app a few years ago and needed some sort of DB to store around 50 million records that had ~10k reads+writes per month with 1 index. It cost me something like $50 to load it up initially, and then something stupid like 10 cents/month to maintain.
The fact that they use it doesn't make what the result is any worse or less trustworthy - arguably it makes it better.
It only becomes a problem if they offload all of the thinking to AI.