most add-ons add more datablocks in order to function( weapons & vehicles mostly)
but there is a limit to how many datablocks you can have.
The paint set uses an outrageous amount when you could easily shorten it to 2-4 datablocks, thus freeing room for more add-ons.
Datablocks are used to
store sounds
make items
make emitters
make lights
make playertypes
ect. ect, so you can probably see why they are so precious.