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.
If i dont want to print a poster, iso6400 is no problem. If you are watching photos on a normal screen, use it for social media or sth else, no „normal users“ will notice this.