Clever trick. Having dealt with very similar things using Cassandra, I'm curious how this setup will react to a failure of a local Nvme disk.
They say that GCP will kill the whole node, which is probably a good thing if you can be sure it does that quickly and consistently.
If it doesn't (or not fast enough) you'll have a slow node amongst faster ones, creating a big hotspot in your database. Cassandra doesn't work very well if that happens and in early versions I remember some cascading effects when a few nodes had slowdowns.
They say that GCP will kill the whole node, which is probably a good thing if you can be sure it does that quickly and consistently.
If it doesn't (or not fast enough) you'll have a slow node amongst faster ones, creating a big hotspot in your database. Cassandra doesn't work very well if that happens and in early versions I remember some cascading effects when a few nodes had slowdowns.