Excel certainly has it's place and is great as an interchange format and prototyping platform for domain specialists. I agree that it's unjustly derided by snobbish programmers. Converting to and from CSV is cheaply implemented and can do wonder as human interface to a system since "non programmers" know how to deal with that.

The problems start when it is pushed beyond its limits, sheets can become undocumented mess of cell spaghetti which users still expect to scale up and grow new features indefinitely. It's hard to determine for Excel coders when they are past that cost/benefit tipover point and move up to a more robust set of programming tools.