This issue has been brought up a few times in the past (most recently in a post by Felemar, I think). I believe it would be a good idea to add protection to artifact pacts so that ONLY the owner can open them. So, in addition to looking cool, never decaying, and holding more items, it would also be a safe place of storage.

I have asked for that thousands and thousands of times....most recently in Imperian when my freaking pack was stolen along with all of my gold.

Too godly... Really, it is. A place that no one can reach but yourself and it isn't the rift? An place where you can store items and never worry about it being stolen? Bah, no, I say.

What's so overpowered about an actual safe place to store items? That's an artifact?

Artifacts are powerful enough just by being indestructible, resetting, stat boosting, holds more, etc. No need to make them everything you ever wanted in one, single artifact. Besides, keeping your stuff safe from thieves is as simple as a couple of basic triggers and a few sigils. Don't blame the equipment when you get robbed. Blame your own lack of research and preparation. I've never liked thieves, but I understand why they exist and I can appreciate the roleplaying it provides. Without risks and conflict, life is boring.