If you want to copy a file in OSX with your mouse you use the menu bar whereas if you want to cut and paste (move) a file in OSX with your mouse then you use the two open windows method that you describe.
They are both very different and one isn't so discoverable.
What's the worst about this is that it's purely a choice and Apple intentionally greys out the cut option in the menu bar.
If you want to copy a file in OSX with your mouse you use the menu bar whereas if you want to cut and paste (move) a file in OSX with your mouse then you use the two open windows method that you describe.
They are both very different and one isn't so discoverable.
What's the worst about this is that it's purely a choice and Apple intentionally greys out the cut option in the menu bar.
Madness.