What these articles always miss is what are the real-world scenarios that use Kafka or RabbitMQ? I've never used one professionally and beyond the async process

What these articles always miss is what are the real-world scenarios that use Kafka or RabbitMQ? I've never used one professionally and beyond the async processing cases I come across in web dev (mostly sending emails asynchronously), or seeing devs using one to handle 5 req/s which doesn't need it, I don't have a good feel for when they are really needed - especially for companies at sub-Uber scale. What real-world cases would you use them for?