Electronics engineer here. I use my HP Prime G2 daily in the lab for basic things as well as quickly calculating complicated stuff, since you can pretty much program it to do whatever you want.

You might say why not use Python or Matlab?! It‘s true that you don‘t need a small handheld device to do engineering calculations where there is a ton of other much stronger and free options out there. But the thing is, a calculator is a pure dedication to one thing. You turn it on, you do your calculation, get the answer and move on. It gets out of your way. Plus it is a better feeling to type stuff using the dedicated buttons in a calculator than using a keyboard.