They are mainly useful for deterministic combo loops where the same prompts, priority passes, targets, mana choices, and stack-order decisions repeat several times
Some, like those above, are as trustworthy as ever - but others aren't worth your time, either because the results are unreliable, they put you at too much risk of damaging your cards, or both
It turns any graveyard into a resource, applies pressure every upkeep, and is notoriously hard to remove
Assuming the staining isnt too bad, here are a few methods that might work for you: Use clear Scotch tape to pick up the specks
Banette PBL 034 is part of the Pitch Black set
Also I totally forgot about the matchprint cards, there is an Ampharos one of those as well and I believe only 2 (?) exist