Backups. Copying photos. Sharing files. As a Mac User, you're probably well served with backups integration in Finder, as well as iCloud, AirDrop, iMessage, and friends without realising it.
Eh? I don't have an iPhone, but my mum does and she uses it fine without a Mac. Everything just syncs to iCloud, if there is some benefit to connecting it to a Mac then I'm genuinely unaware of it.
Even if it was still a thing (and it really isn’t, imo), libimobiledevice does a decent job already, and given a little funding it shouldn’t be super hard to close the gaps and build a nice UI on top of it. But that’s not happening because very few people care about it at all.
Now, AirDrop support is a completely different beast. But it requires hardware support (promiscuous mode, iirc) that many common chipsets simply lack.
The only integrations that matter to me are Messages and notifications for phone calls, neither of which are even available on Windows AFAIK, and could just as usefully be implemented as a Web app as a native Windows app if Apple chose to do so.
Oh, and USB tethering, but in my recent experience that's harder to get working on Windows 11 than on Linux (had to find the correct driver manually on catalog.update.microsoft.com as neither Windows Update nor any of the Apple Windows apps installed it, only to have some update or other remove it without my knowledge or consent a few weeks later).
Your response and the parent sounds like the comments on DropBox thread. It is detached from reality of consumers and fails to contribute direction that can actually move the needle.