I apply adhesive mylar to my em games. No bubbles, just install like a screen protector. They are obviously beneficial and prevent playfield wear so they are a no-brainer.

Absolutely.

I am wondering how adhesive mylar can harm the playfield if it's for home use. The PBR mylar will last for many years.

An adhesive mylar platter works better and cannot damage the playfield. There is no way dirt can get under it.

I agree with waxing the area prior to application. I have used the floating mylar in the past, but I gotta say that after a relatively short period, stuff was getting stuck underneath it and it only takes a speck of dirt to do damage. I had to touch up the area and then applied the adhesive mylar rings.