Cliffys hide wear, hole protectors like Mantis and others prevent it!
Here is a picture of my Tron Pro scoop area. I put a Cliffy on before 1 game was played and the game has around 1,000 plays now (had the protector removed to do some cleaning). The scoop area still looks brand new, so I'd say the Cliffy has done it's job of preventing wear.
I'll be putting a new Mirco playfield in our MM this summer and I'll definitely be installing the protectors as I do the playfield swap.