No calculator which can't handle expressions with brackets is any use for anything important. And ofcourse basic calculators, and the sort which come preloaded in phones are even worse, many lacking not only bracketing but lacking square rooting, trig functions and exponentials.
I can agree the Casio fx-whichever types are good for physical calculators when you don't want to turn a PC on, or when you need to type in a calculation without taking the cursor of the computer off something so as to use an on-screen calculator (can happen when doing CAD if you need to check something during a click-and-drag operation).
I find the best option most of the time to be SpeedCrunch (on Linux) though, all the advantages of a casio type scientific calculator, but you can also copy and paste numbers or expression to and from whichver other program you're using them in. The only advantage the physical scientific calculator has is that you sometimes have to guess what letters to type in SpeedCrunch for the more rarely used functions, whereas all the function calling keys are simultaneously visible on the physical calculator.