Not a scientist, but, interested in these things.

I would say it’s because spicy foods have highly volatile aroma compounds. Tannin and acids aren’t as volatile. Any aroma we perceive is the result of volatile molecules, solubalized in our mucus, binding to receptor sites in our olfactory epithelium - in other words, olfaction is a chemical sense. The tannic mouthfeel of a dry red wine is (if I’m not mistaken) a result of nonvolatile acids acting mechanically on the tongue, so olfaction, a chemical sense, doesn’t come into play in that mechanical sensation of acidity. Also consider that the tannins in a red wine are in a liquid solution. Fine, dry citric acid powder will irritate the nose if you breathe in the particles, just like fine dry cayenne pepper will.

Not sure what you mean with cooling. Something like camphor is highly volatile, and gives a cooling aromatic sensation. Think eucalyptus, fisherman’s friend, vick’s vapo rub, things like that. Do those smell cooling to you?

Metals don’t have volatile aromatic compounds in them at low temperatures, but, they definitely smell like something when they’re red hot. Again, the idea here is that metals are heavy and nonvolatile, so they’re invisible to our noses at room temperature, unlike say, a freshly sliced jalapeno pepper. Out of curiosity, what tastes metallic to you?

One of the strangest elements of this story is that the Village People and Rufus Wainwright are on the Trump campaign playlist.

You’re right to point out the difficulty of preparing installation media.

Also, for the average person, friction will probably happen during installation - possibly having to circumvent safe boot to install and run a new OS (knowing how to enter the bios, feeling comfortable playing around in the bios, knowing how to even disable safe boot once you’re there, not exposing your device to security vulnerabilities by having safe boot disabled), the need for an existing understanding of how partitions work and how the partitions are structured on your specific device in order to test the waters with a dual boot setup on a drive that has data/functionality you want to preserve. Needing to know the ‘what’ and ‘why’ of swap, /home, and /root partitions. These points all came up on a recent installation, and I’m sure they would scare some people off.

Installation will be easy if you have the time, motivation, existing knowledge and/or bandwidth for a learning curve. But not everybody has that.

And that’s just installation, to say nothing of the actual use of the desktop environment, which is not as intuitive as its often claimed to be.