As someone that keeps a pretty robust collection of scrolls and magic items to use outside spells on special occasions only, I don't personally find 712 difficult to come by at all. I suppose if you're the type that stays completely spelled up at all times it could be a good item, assuming that character doesn't already have another way to access 712.

Also, I feel that the comparison to the other thread may be apples and oranges, as both items in the other thread have enhancives in addition to 712. The OP here did not specify any enhancive properties. The pinworn aspect of the item only adds minimal value in my opinion, as for many it would be a wear, rub/tap/whatever, remove and stow kind of item.