I can't confirm right now, but as I recall, macOS's Spotlight search defaults to giving results from the Internet as well as applications, files, emails, contacts, and all sorts of things. It prioritizes local applications though, at least in my experience, and it returns those results quickly. On my work Mac, I've disabled most other options since that's my primary use case for it. On my test Macs, there's typically very little on them besides applications so I'm not totally sure how the defaults play out in practice these days.

I'm a few steps removed from desktop support at this point in my career, so I might be a little mixed up or out of date in my understanding.

I think there's a lot to be said for having a single point of entry for search. Beginners might not distinguish between searching the web and searching local files. That's a weird idea to me, but I formed my habits in an era before "web apps" and "cloud storage". To me there's a bold broad line between local resources and network resources, but for a new user I can see how this distinction would be confusing.

I've found KDE's system for search confusing, since it has two different system search bars as well as the folder search bar in Dolphin. I frequently find myself opening the app search and typing in some simple arithmetic, forgetting that the calculator function is in the other search field, unlike on Mac or Windows. This isn't necessarily "wrong", but I do appreciate having one less thing to hold in my brain when I'm working on Mac or Windows, and I think the unified approach greatly improves discoverability.