Simply put, It's fun to own actual production art 
from my favorite anime titles.  It still 
continues to amaze me that these cels are the 
building blocks of these great shows.

And even though I know how the process of 
animation works, I still watch animation with 
childlike eyes -- without thinking of cels and 
backgrounds and dougas and gengas.  It's as 
though I know the magician's secrets, but the 
tricks still astound and delight me.