I used it to enter my school's science fair where I wrote a program that was a couple thousand lines to calculate, chart, and explore the relationship between musical notes and frequencies. I didn't have a thesis or anything, just did a bunch of programming, and the judges did not care for it haha. At the time, I didn't even realize it was "programming" a computer, it was just fun!
Once I started to learn to program for real, I thought it was weird that I had to type all the characters myself rather than selecting from a list of pre-defined functions!
I remember hacking a loop into TI-Basic by having programs call into each other, since there was no looping control flow built in.
Never did write anything more advanced than TI-basic, I'd heard horror stories of people bricking calculators, and mine was an emotionally sensitive hand-me-down.
My misconception came from an article I read at some point which described assembly/C (I think) programming as more risky, and I just took it at face value.
The one thing I was never brave enough to do was overclock. Supposedly it was just unsoldering a capacitor which would do something like 3x the clock speed.
Always possible I was just an idiot. I remember having looked it up, but I was also a dumb high schooler at the time.
Limitations lead to creativity.
And yes, it was highway robbery at $90+