I worked in medical and banking...these industries seem to run on Excel. Performance is an issue, and the amount of "legacy" code running in macros/vba is staggering. You are talking about thousands of excel spreadsheet which is each like it's own little application.
I recall talking to someone at MS about .NET 4.0 and I asked what were the big scenarios -- and I was surprised to hear that Office programmability was one of the top scenarios. He didn't know exact numbers, but he said that there may be more lines of .NET Office code (VSTO and VBA) than ASP.NET.
Go and ask your random analyst friend if they know VBA, and you'd be surprised how many know it (and with it know things like dynamic typing, implicit arguments, event handlers, etc..).
