Personally, I find drag-and-drop handy sometimes but it's very constraining. You have to go through non-standard motions to complete any more that is more than trivial, always holding down the primary mouse button and thereby losing your primary way of interacting with the interface. In other words, sure, if you have a clear view of your destination, then yeah, drag and drop is fine, but in all other instances, it becomes clunky.
Cut/paste is incredibly quick and doesn't sacrifice usability of your interface or input methods between the two ends of the transaction. Windows seemed to balance this out well, where you could drag and drop most of the time, but you could also ALWAYS cut/paste. I despise that I can't cut/paste in finder. Which is why I use PathFinder instead.
The danger cut/paste DOES pose is it fundamentally unlinks the start of the transaction and the end. In between, you can do literally anything, which may mean losing track of what's in your paste. Still, I'd call this a fair trade-off, specifically because it is non-destructive for files. You won't lose a file to to paste. It just stays put.
On Windows Ditto, and on Linux CopyQ (among others, and there has to be something like that for Mac) solve this problem, by giving you a preview of what's in the clipboard as well as the history copies you made.
Then they are shocked later when they paste those files into some random location and can't figure out where they went.
Dragging and dropping does not have that issue. Users find it much easier to learn.
Open the source window. Open the destination window. Drag.
Macs used drag and drop for file management between windows representing separate locations on disk. Windows users tended to select files and choose cut or copy then navigate to the second location and paste.
The same held true for moving content between documents in an application or moving content between applications. Mac users preferred to use drag and drop, while Windows users relied on copy and paste.
The problem with keeping every window maximized is that you're giving up system wide drag and drop as the primary user interaction method.