I wish the article talked more about why people use Redis as a rate limiter and why alternatives might be superior. Anecdotally I see the following play out repeatedly:

1) You probably already have Redis running

2) Adding a "good enough" rate limiter is easy

3) Faster solutions are usually more work to maintain given modern skillsets

If you are a b2b SaaS company odds are your company will exceed 10 billion in market cap looong before Redis rate limiting is a meaningful bottleneck.