Slabbing, or to be more precise, grading and encapsulating, has not proven itself to be a reliable means of defining value, authenticity or even condition...

Nothing else needs to be debated after this portion.

There's no promise from an encapsulated chip that it:

1) Is Reliable
2) Defines Value
3) Proves Authenticity
4) or certifies Condition

What you do get, is a chip that's sealed in a plastic case, for a fee. Nothing more.