Carving into stone, also used for attempted permanent storage, is pretty expensive. “A simple granite lawn cemetery headstone might cost around £700.” A few sats isn’t too bad.
Sure, a few memos here and there aren't too bad. But for large amount of data it definitely runs up.
I once saw a presentation by Vitalik Buterin where he explain how storing data on Ethereum generally is 1,000,000x more expensive than on a centralised server like AWS.
