Part of the motivation is that I like to play with music programming, and by writing my own code to sequence music, I can write a program that will have exactly the workflow and features that I want. I play with hardware synths because I enjoy having physical knobs I can turn, but there are many free software programs that will connect via the MIDI protocol, both synthesizers and samplers. To conclude, I will note that although I came up with the idea on my own, I wasn't the first to think of using a spreadsheet program to sequence music.