Having a very low latency, durable write destination is a superpower for lots of database architectures (or things that share architectural details with databases, like some filesystems).

Optane had much lower latency than other types of durable storage, and also had very good endurance compared to NAND.

At a prior employer, we made extensive use of them as ZFS SLOG drives for large database servers. They made fsync very inexpensive.