Harder or easier has no relevance. Technique is a 
mechanical process. Its that thing you do after 
you've already created the art and just need to 
complete it. 

The only time that I think technique in and of 
itself can be considered art is in some forms of 
fine art, where the sensitivity of the 
application is most important. In cels, I think 
that sensitivity lies within the drawing of the 
image, not the filling in of colour. A genga or 
douga has that. And all these digitally painted 
anime still use genga and douga.