I was intrigued, so I downloaded the mod.
It sets the min_count to 1 for every POI they listed in the rwgmixer. It also sets the bias to 20 for each of those POIs.
First, setting min_count to 1 will be decently effective, but not perfect. Those POIs still depend on a Tile appearing that will support their placement and enough of those Tiles appearing to give each POI a chance. The modlet cannot make that happen. In one case (at least) it even configures a POI that isn't tagged to appear in the game, so that one will never get placed regardless of the rwgmixer.xml.
Secondly, setting the bias to 20 just tells me they don't understand how bias is used. Doing that selectively overwhelms the bias calculations such that the tier of other POIs won't be relevant anymore and it might mess up trader placement. Doing that across all the POIs just puts all of the other POIs at the same level as the traders and doesn't otherwise affect the math... unless you add custom POIs (more on that later). Actually, it might move trader placement to last as I don't think they have a tier to add to the calculation. In short, bias and weight options are tricky. You have to know the algorithm to use them effectively.
Third, it overwrites three TFP special cases for rural filler lots, gas stations, and the rural outdoor wedding.
Fourth, none of these changes would apply to any custom POIs you get from other sources. In fact, the bias setting will make any other POIs appear infrequently if at all.
Personally, if you want this rwgmixer, I'd remove all of the bias="20" entries for every line after the "UFFBASEE" comment. If you still want to mess with min/max appearing, then go for it.