I have over 3,000 8R coins at present and anyone familiar with me is aware that most are counterfeits. The number of (real) coins in my collection fluctuates as I buy and sell, but that is a good average number. Only 20 of my 8Rs are in slabs because once they are encased the edge is lost to sight and the edge of an 8R is arguably the most important side. (I do have an ANACS encased counterfeit).
The edges are important in particular with regards to the Portrait 8Rs that were forged in the US in the 1800s for use in China. These counterfeits are full weight silver and use dies so accurate that most are NOT identifiable from the obverse and reverse dies at all. The forgers were the same people who were responsible for the high quality copies of the
Morgan dollar that were such a problem in the late 1890s. The micro O forgeries are examples of their work.
Without a view of the edge, you are relying solely on the expertise of the grader who encapsulated the coin. I do not have a great level of trust in that regard - especially in connection with older efforts.
I also object to hiding the edges of Cap and Ray 8Rs because of the number of different edge designs used at the various branch mints in Mexico. No two mints used the identical edge anytime before the 1870s. There are many years where two or more edge designs were used in one year. Anyone that owns 8Rs from before 1840 should really look at the edge designs to see how many different pairs they have. Even with common dates it is often hard to find exactly identical edges, because the mints employed numerous edging mills.
There are also numerous overlooked mint errors associated with the edges. The most common is the edge that reverses half way around ((((())))). The most common real coin with this error is the 1835 Zs 8R. I estimate that nearly half of the production that year was made with the reversed edge. The vast majority of reversed edges are however counterfeit. For some reason this error in mounting edge dies in a two part mill happened more often with forgers than with the mint.
Another interesting variation occurs when two different edge designs are used on ONE coin. I have a few real 8Rs where there are two distinctly different edge designs used. In some series you can actually develop a list of the edges and in which years they occur.
The rarest of the edge designs is the unique (so far) Profile Eagle 8R that was struk on a planchet edged with the colonial edge design. Dave O'Harrow speculates that left over planchets from the Iturbide issue were coined as Profile eagles. Can you imagine hiding such a rarity in a slab? Have all the slabbed Profile Eagle 8Rs been checked for the edge error?
Later in the series when the edge mills became steam powered and they were made to accomodate multiple blanks at one time - the number of double and triple edged planchets grows.
Just a few random thoughts.