[overnight5349]

Yes. There are some things that just work better with a dedicated tool. Sure, my computer has a calculator app, but it's fiddly, the keyboard doesn't physically have buttons for all the operations, so I have to go and click on things. If I need to compute something and copy data to/from other windows, I have to deal with moving windows around to make room.

I do use the calculator on my computer. Quite a lot, in fact. But it's just annoying enough that I keep a pocket calculator on my desk at all times.

It's really great for when I'm doing calculations in my head and need to quickly do some operations. It's just ever so slightly easier to slide over my physical calculator and punch some buttons. It helps me stay in flow and keep all the numbers in my head. The calculator app is just a little bit too annoying and the physical calculator is just a little bit more functional.

As for model, no idea. Some Casio scientific calculator. I bought it because it advertised it could operate with hex or binary representation, but I never figured out how to make that work.

I would prefer a TI-84 or one of its decendants any day. I used to use a TI Nspire, it was really good. It even did 3D graphing and calculus.