I'm certainly not the person to define rare as it pertains to chip collecting.
You would most likely get a plethora of opinions.

I will say that rare and the difficulty of obtaining a chip are two completely different things.
Why shouldn't rare apply to all chips? Would a house chip that there were only 50 examples that were known of be any more "rare" than an LE with 50 pieces issued. I think the answer here is a plain NO. One might be more in the demand but demand is a different issue.

IMHO perhaps having 5 of something might be considered rare. Certainly NOT 100