Lets face it: even if the suggested use of the Handy Haversack on the DoMT was RAW, which I personally don't think it is - would any sane DM let this happen?

Since artifacts exist entirely at the whim of the DM, assuming this reading was enforced, you'd be bonkers to ever put one into a campaign. Essentially you'd be saying to every PC (and NPC, for the matter) in the world "Here, have a whole bunch of crazy powerful permanent buffs and other benefits for free".