Strange how preferences for metal treatments evolve. If I recall correctly, 3-in-1 Oil was the poorest oil for rust protection in the test that found Eezox the best by far. (The motor oil is obviously providing the protection desired.) Rem Oil also performed poorly.
Under ordinary storage conditions, most any preservative will be adequate. It is under extreme conditions that the differences become apparent. The Eezox test was a salt spray test and extreme humidity test as I recall. The "extreme" part comes in when a pipe breaks, a roof leaks or the basement floods, wetting down the storage area. THEN the best products, AND plastic bags, prove their worth.
I stored guns in ORDINARY plastic bags for decades before I built my vault room and never had a problem of any kind, so I am skeptical about the dangers of them for storage. Before the gun rugs took up too much room in my limited storage space, I stored guns in them for decades as well, again with no problem. In both cases, I had treated the guns with my preservative of choice at the time (first CLP and then Tetra-Gun), and put them in the bags "bare."
Now my handguns are really "bare," stored in my vault room standing on their muzzles in filing cabinets, coated only with Eezox.