Complete waste for anything math related for me. Did act as a proper gateway into coding though!

It really depends on the level of the class and the goals. Usually by the time you're getting to calculus you're moving away from simply calculating a numerical answer anyways and the problems where you do need to find one just to test that final step can be finessed so they're simple to calculate by hand and eliminate the problem of full computer algebra system calculators that can handle the symbolic manipulation too.

Personally, playing with the graphing and algebra functions on the calculator were hugely informative. Rapidly trying out different things, seeing how they looked how tweaking things would cause adjustment, all added educational value.

I feel like graphing calculators enable exploration in a way that doing it manually with pen and paper cannot. Obviously, pen and paper is super valuable as well, but I feel that they are complimentary.

Back in the day the feature I liked most about my TI-82 was the amount of information that could fit on the display, the formatting options available, the ease of entering and editing what you entered, and the amount of past entered formulas that would be saved and how easy they were to retrieve. It made doing large blocks of basic BEDMAS math very quick and less suspectable to errors caused by accidentally hitting the wrong key entering in large formulas, and very easy to go back and find out where I messed up and quickly retabulate everything.

All of that mostly comes up in physics and chemistry were its about knowing what long formulas you need to plug the numbers you have available to you to find out what you need to know. Oddly enough their seems to be very little benefit to using a graphing calculator in a actual math class.

In my case it did. I took "advanced math" (trig, mostly) in high school from an abysmal teacher. Ignoring her and developing an intuition through graphing was the best thing ever. I had the best final grade in the class.

They were brilliant in electric engineering classes. I found these calculations very tedious.

For maths not so much, as it was less about providing a numerical answer, and more about understanding the question.

I don't see the need for it. The only time I ever needed to graph a function was to answer a homework problem that specifically asked me to. Having your calculator do it misses the point.