Necessary? Well, that depends on how you define the term. If you're into AES there's a good chance that you're a collector or at least concerned about having collector's quality goods. As such, yes they're necessary. Are they requisite for your enjoyment of the game? Not at all. But for most collector's, mint and complete means that the manual has a baggy.
And all this anal rentativeness is what drove me from homecart stuff. It required a ritual involving sterile hands and the deftist touch just to get out a game to play. And then I had to worry about the corners of my inserts and even the cartridge itself getting scratched up from play. And I NEVER actually opened the manual on any of my homecarts for fear of marring anything.
I do miss the pride of owning a huge collection of NGH stuff (yes, there is some of that), but I feel a bit freer now having only bare MVS carts.
