It hasn't been a long time since Valve has declared about their future Steam update called Steam Direct, which is without a doubt one of the most vital changes they’ve made so far, but it comes with a great cost which has made indie game developers to consider putting their game up on Steam.
I'd like to add in that the pay to post thing already existed even before Steam Direct, it was called Steam Greenlight. By purchasing Steam Greenlight a developer was allowed to put on the store an unlimited quantity of games just for the cost of 90€ or 100$, but with Steam Direct comes benefits that not just anybody will be able to upload bulks of games, unless they have the pocket to do so, which is why most Indie developers would prefer the price to be the same such as Steam Greenlight.
The reason why this change has to be made is because if the fee is too low, then more people are going to post their low-quality games on the store which will have flaws in their structure from a professional perspective, which will make the game completely blunt and not playable. The recommended section is going to get flooded with games that are not even worth your time and it's going to be much harder for Steam to proceed into a game quality check to see if the game qualifies to be put on the spotlight or not.
Throughout this stressful moment for Indie game developers, those who don't have the needed amount to pay for the fee will crowdfund it, making the developing of the game either rushy or not having the result that the developers promised. This will cause the Steam market to get a little bit more space for games and developers stressing over date release times to "satisfy" their funders and fans to draw in as much money as possible.
"Papers, Please" is a good example of a high quality game from Steam Greenligh
Another good example is UnEpic
Broforce has also been greenlit!
That being aforementioned, none of those two options seem to be correct. therefore, Valve's approach should take more into consideration whether the final release of a game is completed and it's playable and not if the developer has a few extra coins to throw at Valve for consumer attention.