Depends. It’s a mix of all the reasons you’ve mentioned, and I’m sure this will vary from person to person. For me, high fidelity audio matters only with headphones, and if I’m listening to music. I can absolutely tell there is a difference with speakers but I don’t enjoy them as much so I don’t care as much.
Similarly I’m not much of a HD4k+ person when it comes to video. I do see the difference but for the most part my brain will filter most visual noise, issues and distortion away while I’m engaged in narrative. I don’t need large TVs nor too much high resolution. PC monitors/laptops/phone screens? I want every pixel you can give me, the higher the resolution the better. Completely different experience than TV. I’m annoyed when I can see the pixels on a screen I’m working on.
I’m with you on the binoculars and microscopes. Yeah, quality does make a huge difference and I would absolutely get the best if I can afford it.
Food- I’m a lazy cook and very picky about condiments. I really enjoy most foods plainly. I don’t mind if my stir fry got a bit soggy or if I forgot to salt the roast. I’ll eat it all the same and be content with it like it had been perfect. For me to really appreciate the difference in food quality you need to add significantly more than 1% effort, so I leave that to professional chefs.