When I was in High School, I had a job in the accounting department of a non-profit. This was the mid-eighties, so a spreadsheet was a giant piece of green paper with cells drawn on them. The department had a mainframe and used computers to process invoices, but a lot of accounting work was still done on paper. I helped file that paper.
At some point, they got a couple of PCs and they installed Lotus 123 on them, but no one was really using them. They knew that I was into computers, and so they asked me to transcribe the paper spreadsheets to Lotus 123 as more of a data-entry clerk.
This work was a seed which grew and grew. At some point I discovered
SUM and showed it to someone. I learned more about formulas and built spreadsheets that could auto calculate when the underlying numbers changed. You know, spreadsheet stuff.
By the time I left, my spreadsheets made extensive use of macros and more complex formulas.
In a very real sense, those spreadsheets were programs, and learning how to do that alongside with learning how to program made me better at both.
I think that a lot of people that are good at Excel could learn how to write conventional applications if they wanted to. Even if they aren’t currently writing macros, the main ideas of cells, formulas, range processing, grid-layout, and styling map pretty cleanly onto application software concepts.