Well, they might want that save-data-and-clean-shutdown functionality. I mean, I don’t personally care all that much for my use case, but it’s a legit want. Like, say you have a USB flash drive plugged into your machine. Those normally ship formatted with exFAT, a Microsoft filesystem derived from the elderly FAT16 filesystem, and most people use them like that, as pretty much every OS out there can read FAT. FAT can become corrupt in the event of power loss. Or say you’ve been working on something in some application that doesn’t do auto-save and have a day of work accrued in the thing and then you get a power loss. Having a few minutes notice to clean up and shut down is legit important, same way that a laptop will issue low power warnings on a battery. This makes sure that you get that notification.
I think that in general, the clean shutdown functionality isn’t as important these days as it was in the 1990s, as most machines are using journalled filesystems that don’t become corrupt on power loss these days. NTFS (Windows land), HFS+ (MacOS X), or ext4 or btrfs (Linux) for most of their storage. But, I mean, there are going to be people who want it. I don’t think that someone has to be wanting complexity for the sake of complexity for them to have a use case where that applies.
EDIT: Looks like HFS+ actually got replaced with a newer FS a few years back as the default on MacOS.