To me, this only makes sense if it's integrated advertising in the browser. Trying to get third party websites to use their advertising network probably will be a very difficult sale.
It could be a way of greenwashing, or whatever the expression is for privacy washing, businesses like meta, Google, by letting them license a "privacy friendly" advertisement platform.
As far as I'm aware, there's only two major online advertising platforms, meta and Google. So breaking in is a third platform would be difficult, unless they could integrate into apps directly through Mozilla's app footprint
driving advertising performance requires privacy-enhancing approaches to data driven marketing. Anonym’s privacy preserving solutions allow you to take full advantage of your data assets.
Fundamentally, privacy and data-driven marketing are diametrically opposed