They’re different databases that do different things with different features and different ways of laying out data. Redis functions as a cache, not a relational database — it’s not merely about speed of response.

Do not use redis as your main database, it will require you to contort very painfully to so things that are normal to most apps. Maintaining Lua scripts instead of SQL queries is a bad idea.

If this is an ad for redis labs then it’s a really bad one.