I could not find any way to link to Spinx coins. I made a low ball offer for this one on eBay and they accepted it. This one being slabbed to me adds a bit of value.
I think that depends on whom you ask. Many (maybe even most) diehard traditionalist Ancients collectors would tell you no, and some might even go so far as to advise you to crack the coin out of the slab. Slabs are widely hated by these traditional collectors. But I say yes, it does... if only a little bit. It adds value by broadening the market for the coin. Many people who are not diehard collectors of Ancients, and who might be entering that market for the first time, like the reassurance a slab offers. NGC slabs do not offer an absolute guarantee of authenticity on ancient coins, but they do add an extra layer of protection. After teetering back and forth over the issue of slabbing ancients, I have come down on the pro-slab side of the argument. I slab mine because the rest of my collection is slabbed, and I like the way they look in the slabs, and so on. But if I collected only ancients, I might go the more traditional, slab-free route. I personally think slabs display nicely. Of course you can no longer touch the coin, and that's a dealbreaker for a lot of folks who like to literally handle their history. But that's one of the tradeoffs. There are pros and cons to both sides of the issue.
Only had one slabbed coin and I freed it I like to have the coin in hand, measure and weigh it myself and enjoy it. Can't do it if it is slabbed. Anyway, to each their own