

This way I’m sure that if for some reason I need to make my drawing bigger than expected, I can scale up the line art and it will keep the quality of the drawing. For example, I always draw my line art in vector layers. Of course, not every artist will use this nor need it.

This doesn’t happen if you drew your image in a vector layer. Usually, if you scale up and down something, the image will lose quality.

The main difference between a raster layer and a vector layer is that you can resize you drawings as many times as you wish in vector, without losing quality. Using Vector Layers in Clip Studio can and will be very useful to you if you tend to resize your work a lot.
