I do. It just works, and it feels better than the on-screen versions. The Windows calculator is atrocious. Some of the emulators for iOS are good, but still feel clumsy in comparison to the real thing, especially for more than adding two short numbers.

The truth is: I like calculators, and I think almost everyone answering in the positive does too. Most people don't care about them, and see their phone as a god-given miracle, I guess, which makes calculators an expensive-ish burden.