One less keystroke to type. Plus, it's kind of silly since it's not uniformly integral at the higher end. I.e., an EX/MT 6 is 80, NM 7 is 84, NM/MT 8 is 88, why wouldn't MINT 9 be 92?
#1 in 1959 Topps. Officially known as Assassin according to stanthemanfan 3/31/2014 and god of minor league basketball according to cammb.