If your teacher advised this ramp, it's because you're playing (as do most people) off the left side of the nail (facing the back of your hand). The ramp keeps nails from catching on the string, and allow a little contact with the flesh of the fingertip. That's it in a nutshell. If you played off the right side of your nails (eg, Thibault Garcia) you'd possibly ramp the other way. And some people don't need to ramp their nails at all. Depends on the shape and movement of your own fingertips, whether your nails hook or not, their length, and what school of RH technique your teacher has learned and is passing on to you. As you progress you may experiment with different shapes.
2015 Connor spruce/Indian rosewood
1978 Ramirez 1a cedar