Typically, digital artists work for themselves. They sell prints, art books, do commissions, T-shirts, etc. This means they can work in the comfort of thier own home and work by thier hours. Of course, they have due dates and such to complete things, and sitting in a chair with your tablet all day can be stressful on one's back!
Really, this is subjective. It depends from person to person. If you're just starting out, people don't really know who you are, you aren't going to get many commissions or sell many art books. Once you get yourself out there, however, more people will follow your art and be willing to shove thier money at you to get you to draw something.
You would think the main way to get yourself out there is to have raw skill. Unfortunately, this isnt always true. Many artists "sell out" to become popular by drawing what people want. Fanart, and in some cases, explicit images. It's sad really, there are a lot of people out there with some serious talent who never make it because they rely on thier own creativity, rather than perverts and fangirls. The art community is a shark tank, and it takes some bravery to dive in.
Part 1