The mods have nothing to do with the bumper

No

This is such a niche use case that I see no need for except for very few people.

A bigger sale will happen just before Xmas. Steam has a lot of sales plus games go on sale throughout the year.

It has always been free. Having said that, if you use it often then throw them a bone every once in a while at a minimum.

A bigger sale will happen at the end of the year. Steam has enough sales annually so FOMO is not an issue.