re HTTP specifically: one major benefit I've seen to even "just" HTTP wrappers for systems is that the HTTP ecosystem is extremely mature, even on relatively ex

re HTTP specifically: one major benefit I've seen to even "just" HTTP wrappers for systems is that the HTTP ecosystem is extremely mature, even on relatively exotic languages / platforms / coding patterns / design constraints / etc. You want load balancing, context propagation, multiplexing, proxying, authentication, request tracing, [anything from a truly gigantic list, both in-code and around-your-system]? HTTP has it. Probably several. And they probably already work with everything you already have, and happily run unattended for years. Kafka... might? Kafka for language X.... might? But probably not. You want to extend Kafka to add X between Y and Z? Does the protocol even allow it? HTTP does, choose your flavor. Odds are even decent that a fair number of your engineers have already heard of or used it. --- There are benefits to specialized protocols, absolutely. But there are also benefits to letting everything just use the same robust HTTP client as everything else.