The reason people ditch number pads is so that their mouse can be closer to them. Feel what your upper arm is doing as you rotate to get to a mouse that's next to a number pad, that is painful for a lot of people. (If you use your mouse with your left hand, then this doesn't matter.)

Personally, I just have a layer that I activate with my right thumb to turn the m,.jkluio keys into 123456789, so it's like having a number pad, but one that doesn't take up any space.