when you have your mouse on the left of your keyboard, the WASD keys are far from your right hand.
The second reason arrow key help a lot of people is : not everyone have an QWERTY keyboard. i'm french, so mine is an AZERTY. to play your game, i have to emulate an QWERTY keyboard. if i don't, i let you imagine the fun when
Q W E
A S D
Z X C
is replaced by
A Z E
Q S D
W X C
that's why many game allow either to map the keys or to use WASD and Arrows
I am working on a Unity project trying different character controllers.
You can configure both WASD and arrows, plus game controllers (it's a pity many games don't use the right stick for camera).
If it helps I found an exampleYou must be registered to see the links
Im sorry i didnt think of this problem before, i'll try to make it more confortable for users with that issue in next releaseYou can install an US keyboard map in Windows, and you can easily switch from French KB to English by pushing Shift + Alt.
Game still have to allow remap of keys, but it give a better play experience for many alpha game