I see Redis as a toolkit that collects a number of solutions to hard distributed system problems in a single tool. It is great for developers that have a number of use cases for these kinds of things but for which there is no need or justification to spool up yet another cluster of containers/vms/servers/load balancers/etc to support it. Redis already has to do these things to be reliable and consistent; directly exposing this ability to clients and modules is a very logical thing to do. Like it or not, Redis is a platform now.

If you really just want fast data structures in memory, use memcached. If you somehow feel that Redis is a better solution for you, perhaps you should carefully consider that you may be placing more weight on its platform features than you realize.