I wonder if Kafka represents an existential angst in these Kubernetized Microservice times. Or is it more simply I am just too dumb to learn and use this shit correctly.
But there are times when you have a problem, and amongst the possible solutions is Kafka.
I've come across Kafkaesque problems only three times in the last seven years: a hosting platform that had to parse logs of over 700 WordPress sites for security and other businesslogic. Putting all events of a financial app backend into datalakes and filtering and parsing all openstreetmap changesets live.
No more daily SQL dumps from offshore to onshore and big batch procedures to genereate outdated events.
For me, Kafka sits in the same area of solutions as Kubernetes, Hadoop clusters, or anything "webscale": you don't need it. Untill you do, but by then you'll (i) have Serious Problems which such systems solve and (ii) the manpower and budgets to fix them.
With which I don't mean to avoid Kafka at all costs. By all means, play around with it: if anything, the event-driven will teach you things that make your a better Rails/Flask/WordPress developer if that is what you do.