Redis was definitely more featureful, and antirez is both an engaging character and admirably humble, so I can see why redis overtook it in popularity - but, for me, memcached has always been the pinnacle of "choose boring technology".
As a platform engineer, I'm happy to support either - but when developers start using some of the more advanced redis features (persistence, replication, clustering), I try to make sure that they've fully understood the downsides of that decision.
This so much. (Ab)Using a db table as a k/v store + the FS can do so much before even considering paying the price of setting up a dedicated caching store. I’ve fought countless foes in the engineering world when proposing solutions like yours just because (incompetent) people feel like caching should live in its dedicated store.