If you have used old MAC OS then you might remember you can’t merge the windows and it was very difficult to work on the system.
Why Merge Feature is Helpful?
It is very difficult to work, if you have to open widows again and again but using Merge feature will gather all windows into single Window with tabs.
How you can merge finder windows in mac
If your fill is filled up with many windows then you can merge finder windows on one window, for that click on the Windows option in the menu than click on Merge all windows.
Right now there is no keyword shortcut right now, but you can make one. This little trick will help to save your lot of time and help to manage the stuff easily as all finder windows will be merged together.