In distributed robotics, there's a lot of things that go 1) pull data, 2) check timestamp on data to see if it's "fresh enough" to be considered.

Redis solves that so naturally with TTL that it's not even worth considering message queues, dbs, or ROS topics for this. Yet, almost nobody does it that way from what I can see (I mean, we did, and it was fine).

I used to use Redis for every project, but a lot of times just using a SQL database is fast enough. Redis is wonderful, and simple but is yet another thing running and has to be checked and invalidated.