HTTP is also very well understood with at least basic monitoring / health management that is fairly straightforward. I know what happens when I make an HTTP req

HTTP is also very well understood with at least basic monitoring / health management that is fairly straightforward. I know what happens when I make an HTTP request. I know how long it should take to get a response, and I know what a success or error response will look like. And since I'm the originator, my log will itself contain all the necessary information to troubleshoot whether the issue is on my side or the other's. That's not to say this can't also be done with message brokers, but unless there's a good reason HTTP won't work well, a lot of this stuff already works intuitively out of the box with HTTP.