I can't help but feel we're at the "aliens watch people eat from space and recreate chemically identical food that has no taste" phase of AI development.
If it were 99.9% chemically identical but they left out the salt and spices…
And so without the correct amount of salt and/or spices, we're talking about food that's very similar, and not identical.
* They might not perceive some substances at all, others that we don't notice might make it unpalatable.
* Some substances might be perceived differently than us, or be indistinguishable from others.
* And some might require getting used to.
Note that all of the above phenomena also occur in humans because of genetics, cultural background, or experiences!
However, there is a broader context: this is supporting an argument against physicalism, and in this light it falls apart. There are a couple of missing bits required to complete the experiment in this context. The understanding that knowledge comes in 2 varieties: direct (actual experience) and indirect (description by one with the actual experience using shared language). This understanding brings proper clarity to the original argument, as we are aware - I think - that language is used to create compressed representations of things; something like a perceptual hash function.
The other key bit, which I guess we've only considered and extensively explored after the argument was formulated, is that all information coming in via the senses goes to the brain as electrical signals. And we actually have experimental data showing that sensory information can be emulated using machines. Thus, the original argument, to be relevant to the context, should be completed by giving Mary access to a machine that she can program to emulate the electrical signals that represent color experience.
I posit that without access to that hypothetical machine, given the context of the experiment, it cannot be said that Mary has "learned everything there is to learn about color". And once she has comprehensively and correctly utilized said machine on herself, she will gain no new knowledge when she is exposed to the world of color. Therefore this experiment cannot be used as an argument against physicalism as originally intended.
All that took was words and a shared experience of smelling.
But, fair point. The gist I was trying to get across is that I don't even know what a plant smells like to you, and you don't know what a plant smells like to me. Those aren't comparable with any objective data. We make guesses, and we try to get close with our descriptions, which are in words. That's the best we can do and we share our senses. Asking more from computers seems overly picky to me.