For a certain type of person who heavily values utility, yeah, go with money. Most useful, the person you replied to has a point.
They’ll likely also appreciate that you know them well enough to know that they would like money the best instead of making the assumption (that would be correct for a lot of people, but not for this particular example person) that they’ll feel money is too impersonal. 😛 Sentiment probably would play a role, with the sentiment still being “you know me well enough to get me the gift I’d like the most.”
I like giving gifts because I feel it’s me showing the other person that I know what they like, that I see them and listen to them. I like receiving gifts that show that the person who got me it knows me well enough to know my likes. I would absolutely prefer money if you’re uncertain of my likes—I also value utility. Even if the gift of money was low-effort and not out of “I know you would prefer money over an incorrect guess at what you like,” I’d still prefer the money. More useful to me and would bring more joy than something I didn’t like.
So I mostly agree with you when it comes to gift-giving, but the person you replied to also has a point!