If you have a datacenter of your own and several VMs, redis would be fine as a persistent store. I wouldn't do it but it would be fine.

If you are in the cloud and have any hint of using kubernetes then DO NOT USE redis as a persistent store. The problem is that redis' master/slave and replication pattern goes against the load balancing and Service objects of kubernetes. Redis was created in a time when it expected physical nodes to be available 24/7 and is not designed for nodes to go away. It can handle it but it isn't designed for it. Two different things.

Redis as a single pod and a cache works great. I would never use redis as a DB. We have DBs specifically designed to be DBs.