There is a less radical way which hides the Panel almost completely:
Go to the "Panel Properties" (right-click on the panel an choose "Properties") then mark the "Show hide buttons" setting (and the "Arrows on hide buttons" if wanted) as shown below.

- Mate Panel Properties
- mate-panel-properties.png (243.08 KiB) Viewed 2703 times
Afterwards you can hide/unhide the panel to the left or the right with a click on the "hide button". This hides the panel and expands maximized windows all the way to the bottom of the screen (see screenshot below).

- Mate Panel hidden
- mate-panel-hidden.png (251.8 KiB) Viewed 2703 times
This way you can access the panel if ever needed and you don't have to mess with the system itself.