Why is the system design interview so important?

I've used Redis in production for almost a decade. Here are my top 5 use cases where it shines:

Caching

The most common use case is to utilize Redis for caching objects or pages. This helps protect the database layer from overloading.

Session

We use Redis to share user session data among stateless servers.

Distributed lock

We use Redis distributed locks to grant mutually exclusive access to shared resources.

Counter and Rate Limiter

These two use cases are related.

We use Redis to track like counts on social media apps, and also to enforce rate limits on our endpoints.

Leaderboard

Sorted Sets is a delightful way to implement a gaming leaderboard.

There are many other features in Redis. What have you used at scale in production?