I've been working on something Redis-y over the holidays, and it has reinforced my view that it's the epitome of a 20%- 80% tool. I've always used the 20%, but anything beyond that sounds useless unless you've encountered the requirement in a production environment. The challenges Redis has been solving for years, never really touched the research/academic community (even the 20%).

Even in the various taxonomies of DBS in the research literature, Redis was mentioned with a wave of the hand as an "in-memory" database, which undersells the important (for me) part of the "data structure" server.

Putting the "database" after Redis could be a marketing misstep. Because it puts you in the is-it-sql territory.

TL;DR: Redis is mostly appreciated by practitioners (web) developers. Academics find it lacking a theoretical foundation, so... meh.