When you need to be able to retrieve the timeseries data for some period of time, storing it in the application memory doesn't really work since the application

When you need to be able to retrieve the timeseries data for some period of time, storing it in the application memory doesn't really work since the application will restart whenever updates are made. Also, redis timeseries offers the ability to downsample to some defined period which is really handy (and afaik isn't really provided by other timeseries databases) as well as set a retention policy.