> if the audience is small, you are just fine sharing vids using the html video tags

Yet people do not do that.

I think that's more a measurement of demand volume than anything. It's a VERY tight squeeze between "I'll just send this file directly to the few people I want to show it" and "I want to show this to anyone" to the point no matter what is done by those people it'll seem like nobody does that unless it's also done in the other categories.