There's no legitimate reason to use URL shorteners. It's only if you want to hide malware, tracking links, referral links, etc - none of which benefit the user.
Curious: any idea how much would it cost to run a year?
Probably not that much, there's not much processing power involved nor bandwidth used (it's really just serving 301 redirects). A bare-metal dedicated server should handle quite a bit of traffic and remain cost effective (compared to their "cloud" equivalents).