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.