Contrary to what you might believe, painting cels 
was actually cheaper than paying a digital artist 
to work on the film back in 1995-96 in Japan (I'm 
getting this information from some friends of 
mine in the industry). Cel painting wasn't 
newfangled technology; 3D and digital ink and 
paint were still rather shiny and new. To cut 
costs, Studio Ghibli only used the computer when 
it was totally necessary, such as complex action 
and morph sequences.