I think it's one of those things where you don't "notice" it, but where it nevertheless has an impact. Sort of like someone might not "notice" the fact that there's more butter or salt in restaurant food, but it's subjectively better than the same meal they cooked at home.
For a more directly relevant example, companies frequently A/B test changes to a UI to see which ones people like better. The specifics of those changes would be pretty marginal if you didn't know what it looked like before (like if you're a new user, you wouldn't notice if the notification was red versus purple, or what the wording in the menu is). Despite this, there are some sites that just "feel" better in a way that you can't really describe.
All of this is a long-winded way of saying that I can't tell if I'm looking at Arial, Helvetica, or this Nebula Sans font unless they were side by side (and even then I'd just be saying they're different, not identifying them by name). But I think the site would feel a lot less modern if it were written in Times New Roman. I think you'd notice if it were too hard to read when small, and I think if it looked "bad," you'd at least subconsciously notice that.
Sure, I'd happily take a more readable, less eye strain, less ink consuming, whatever, font. What is announced here, however, is "A versatile, modern, humanist sans-serif with a neutral aesthetic, designed for legibility in both digital and print applications" which is just designer speak for NIH.
For a more directly relevant example, companies frequently A/B test changes to a UI to see which ones people like better. The specifics of those changes would be pretty marginal if you didn't know what it looked like before (like if you're a new user, you wouldn't notice if the notification was red versus purple, or what the wording in the menu is). Despite this, there are some sites that just "feel" better in a way that you can't really describe.
All of this is a long-winded way of saying that I can't tell if I'm looking at Arial, Helvetica, or this Nebula Sans font unless they were side by side (and even then I'd just be saying they're different, not identifying them by name). But I think the site would feel a lot less modern if it were written in Times New Roman. I think you'd notice if it were too hard to read when small, and I think if it looked "bad," you'd at least subconsciously notice that.