So you imagine companies spending sats on those kind of chat messages? Zapvertsing-style.
Reminds me "permission-based marketing" a let's-make-ads-less-annoying technology that never took flight due to the lack of practical micropayments (cf Adkeeper https://en.wikipedia.org/wiki/AdKeeper ).
Discussion
Your Nostr client could have a toggle for "Pay to spam me, and here's my sats-per-impression-threshold". Or it could be relay-based; maybe that better decouples the development of spam-for-sats from any particular client. Just riffing here.