It’s not unheard of, similarish to many core licensing schemes. Like mssql.

Not the same thing. The equivalent would be mssql charging by web server connections to it.

In some sense, core licensing is worse, in that you are also paying for idle capacity. But when you try to scale by activity, I think you will see it is not that much different.

Like BYO wine I guess.

A lot of server software does that. People were paying absurd prices for fast Xeons to save on their Oracle bills.

Reminds me of a customer that had in their contract requirements GHz amount so after we won the contract we digged out some old P4 based Xeons (everything after for a long time had lower clocks) and they got their stuff ran on old junk because it would be breach of contact not to.

It was govt thing and they are required to put a new bid every few years and their bid was EVIDENTLY "just list what our current hosting provider has, we can't be arsed to spend months migrating infrastructure every few years", but the clever weasels in the sales managed to get them.