@richpuchalsky this is a shockingly cynical way to view it. Like holy shit I have no idea how you could possibly reach this conclusion.
I don't know what circles you frequent to give you this kind of impression, but the technically literate people I surround myself with do it as a mutual aid kind of thing most of the time. Usually out of an abundance of caution or concern about the intentions and integrity of *other* people hosting servers, such that their local community (usually and especially their immediate friends) can feel safer or more welcome. This is the primary and most immediately identifiable motivation I can find anywhere.
Beyond the fact that, though seemingly this escapes you, a lot of people find doing this hard thing of creating and managing a service for people... fun? People may surprise you.
The world can be an evil, awful place, but I think it may be worthwhile to you to analyze how the lack of benefits to hosting a mastodon server may actually lead to *more credible people* by volume than the circumstance in which there was some cynical, material advantage.