Polyfill mod with Coin Mod

Hello, has anyone tried the polyfill mod and the coin mod together?

What’s the coin mod?

I was asking the same question. Is it adding coins to add weight?

I don’t think it’s for weight. It changes the sound quite a bit. They just line up the coins on the bottom of the case and it makes the sound more thocc. It’s like a plastic case turns into an aluminum case.
There are several examples on the internet. It seems to have a serious effect on the sound.

Would this be a PCB shortage concern? Especially for flexy keyboards with POM/PC plates.