She also doesn't identify herself as a mailman but steve does, maybe its because she did deliver something to steve without him realizing.
no one really knows why paper mail carriers are there anymore. nowadays we mostly use email for everything. which is another reason why 'mailman' seems like a fun idea. everyone knows what it is, and it seems familiar, yet in the back of your mind, what are they really doing? it's just a person who visits your house every day. which seems nice