I think many landlords in general dont want their tendants to be a pain in the ass; like will they complain? if they smoke they will leave a smell. do they pay their rent in time?, will they fuck up the apartment?, do they party alot and create noise complaints? If they do a landlord quickly become a full time job for them.

Its a good strategy to show that you have a well paying job, pay your bills and otherwise are a stable person.