That seems like an interesting choice.

As an individual, I don't think I'd ever pay for promotion of a package unless I had moved my career to providing support for open source packages.

I can imagine companies using it as a marketing exercise for their open source efforts. That might not be a bad thing as packages backed by companies tend to be better, more mature, have better support.

However I can see this then being abused by SaaS companies using this as a way to advertise their service. i.e. they provide a package that integrates with their service, so while the package is open source they are making money on the use. I can imagine this significantly degrading the quality of packages.