Having watched a few 2D artists paint on an iPad
The 3D has many differences to 2D work. 3D potentially has dozens or hundreds more functions to access over 2D but the main issue is the ability to quickly and accurately target 3D parts for manipulation using a mouse and screen cursor. Another advantage is that using mouse and cursor allow far less viewer resizing to get at the parts. Most of the time with laptop work, the screen can remain full size. When I do need to resize the view, I instantly use the mouse wheel to do that and can get the exact size of view that I need (also - instantly). A person would need to learn to use the mouse and cursor in 3D modeling to understand what I am saying and actually experience the quickness of it. The Wings 3D modeling software which I use for the 3D creation stage of the modeling is made for speed and accuracy. It's great! I regularly get that stage done faster than most people using other software, even if they use the commercial favorites. (The applying of 2D texture to the model is also extremely fast in Wings 3D). For animations, I use other software.
I hope that this helps people.