It's ONE extra click.
The current way:
Click on town, click on signpost, click 'walk' = 3 click.
Your way:
Click on the map, click 'walk' = 2 clicks.
It would be silly if you just clicked on the map it it started walking to that town straight away. You need to see how long it will take first.
It takes ages? Then your internet connection is too slow, or your computer is too old, or you are too impatient.
I just don't see this winning the 'Benefits vs Work Needed' argument.