While this isn't much of a company relationship thing: If you're getting paid every 2 weeks, sometimes you'll get paid the first/third week of the month and sometimes the second/fourth, which can be a pain if you're trying to keep a consistent amount in a checking account while also having bill pay and auto-transfers to savings/investment accounts.
Or, tl;dr, it makes it easier to automate money without leaving a large buffer of cash in a checking account.
