I used hand held light meters for 25 years when I shot film. This picture of an American Eskimo puppy was taken with a medium format film camera (Mamiya RZ 67 II), studio lights, and I determined the exposure with a Sekonic L-558 hand held meter. As you can see, the exposure is perfect. For a white subject on a black background, the exposure is challenging but the meter provided perfect results.
In the digital realm, I never use a hand held meter. All I do is look at the LCD monitor on the back of the camera, and if the exposure is not right I tweak it. In the case of flash, to alter the exposure I can raise or lower the output of the flash, change the lens aperture, or change the distance of the flash to the subject. I can also add diffusion material in front of the flash. I'll take another test shot and make a final determination of the exposure before I shoot in ernest. It takes about the same amount of time with and without a meter to arrive at the ideal exposure.