Arrow keys for movement, AND being on the left side! That's kinda rare!
For decades it's always been absolute insanity to me to have directional controls on the right. I get it, the arrow keys are on the right... But so many games have been using WASD as the de-facto standard for so long yet indie developers and the odd AA/AAA game opt for arrow keys. When was the the last time you used a gamepad controller with movement on the right?
As someone else mentioned: this appears to be the lingering standard for Japan.
And I'm not saying that it's "bad"; just weird to me.
I do see the benefit if your input device has ghosting issues, and arrow keys provide some leeway for rollover.
To each their own - just use whatever is comfortable, but I'm still finding it surprising to this day.
I just wanted to play with one hand, and i dont find it comfy to play with my left hand.
Also teeechnically it is arrow keys as directional, but its the numpads arrow keys. I use the normal arrow keys for things like dodge and abilities.
I use the arrow keys because i can rest middle finger on 5 which can be set as an action/okay/attack button and with this position, 0 is the perfect resting space for thumb, so jumping and sometimes cancel are good stuff. Its only a slight shift to the left to hit the right arrow from the 0 button too, making it a good dodge or sprint button(unless the game has sprinting and jumping being a thing...)
The rest are just convenience buttons. + is great as a menu button. - Is great for alternative menu butons (like map). 7,9 are great for abilities if theres multiples, and also good for games that let you tab through pages in a menu (like most rpg maker games)
I do have a setup for the jkl; side of the keyboard as well, but its a little different. I had to set it up for some rpgmaker games that insist on making sprint locked to shift, which autohotkeys doesnt handle well.