Intersting this is getting mentioned -- Disney's relationship with Chase dates back to the mid/late 90's when they were known in many places as First USA and Bank One.
Prior to Chase, their "official" bank was Bank of America (back when BofA was known as a "west coast only" bank) -- they even had a full-service branch on Main Street U.S.A. inside
Disneyland (plus, the Disney/BofA relationship dated back to the 1930's when BofA financed Walt Disney's first full-length animated feature, Snow White and the Seven Dwarfs). Due to interstate banking laws at the time, the BofA arrangement did not carry-over to WDW (as there were no bank branches in Florida until 1999).
In addition, BofA also financed the construction of Disneyland.
Actually, I am suprised Disney is shopping-around for a new official financial services provider, as there are only a handful of large, "national" banks with a presence in both California and Florida (as best I can recall, Chase, BofA, and Wachovia/Wells Fargo are the only ones).
Like one of the PPs, I like the convenience of having Chase ATMs around Disney (I have an account I use exclusively for vacationing, there).