Although the megapixel fetish race is the one that gets the most attention, I think the ISO equivalent is also pretty amusing (in a "shakes head, looks baffled" kind of way).
Now, I should preface all this by mentioning that I don't have a "genre" of photography. I just photograph whatever attracts my attention at any given time, and that can be day or night.
Recently I saw a camera review in which the reviewer was showing pictures captured at ISOs that would have been considered witchcraft even ten years ago. They looked like garbage - noisy as anything and generally an aesthetic mess. But apparently the fact that they were taken at stratospheric ISO levels means that the whole world must see them because, I don't know, reasons.
Although I've used cameras that are well known for good high ISO performance, a look through my Google photos collection shows me that I almost never go beyond ISO 3200, and I would guess that less than 5% of my (tens of thousands of) photos are shot at that sensitivity. On a usual day, I find that if I have a fast lens (F2 or quicker), I can get almost anything I want to shoot without going past ISO 800, or 1600 in a pinch.
I'd be interested to hear from people who do use these 5-or-6 digit ISOs on a regular basis, and what they shoot that necessitates these ISOs. Let's hear some thoughts.
My ISO is not your ISO. Each camera has a different ISO for the same setting, say ISO100 will look different on different cameras, even from the same brand.
My Nikon d5100 gives garbage on anything over 100, my A7iii can still look good at 6400, my A7Rv I dislike anything over a few thousand.
Each camera behaves differently, and the what is acceptable also varies on the available light, a brighter scene with a high ISO can look cleaner than a dark scene.
It's all highly variable.