Holding what bag though? I still dont even understand what this is - how it makes money for the devs and how it makes money for anyone else.
Download game for free
Click the banana
Get a free banana skin that can be sold to some sucker for real money
Sell banana skin on the Steam market for $0.03
Buyer pays $0.03 - Valve gets $0.01, Dev gets $0.01, Seller gets $0.01
Why would a buyer pay $0.03 (or more) for a virtual banana skin for a free to play game? Either they think it looks cool(?) or they think the value of that skin will go up on the Steam marketplace in the future (probably not). Either way, Valve and the dev take a cut of this tomfoolery. Maybe the buyer will eventually resell this themselves for $0.05 to try and recoup their costs, in which case Valve and the dev get another penny each from this same skin.
It's the same business model that's allowed Valve to make hundreds of millions of dollars on Counter Strike gun and knife cosmetics while providing the game itself for free. The only difference here is that there isn't an actual game, just a screen with a banana on it that you click to win.