An alt take on grading:

Grading can be great if for no other reason than it preserves your coin in its best state. You need never worry about fingerprints, etc when in a slab.

While each buyer must do their diligence, and a coin being in a slab is never an absolute guarantee of authenticity, it does "evidence" authenticity, and for an entry-level buyer who may not have seen a cas coin in person before and has no frame of reference, having the backing of a graded coin in a slab can be the make or break decision as to whether or not someone wants to take the risk of a purchase.

I highly recommend getting coins graded by a reputable company.