A digital multimeter is considered a more modern that is considered easier to distinguish than an analog meter. So why do some multimeters show an artificial bar or dial on the screen? Are they trying to appease people who are used to the analog meter look?
Perhaps, but sometimes the bar can be quite useful. Professional meter manufacturers are aware that it can be annoying if the numerical digits change too quickly, making it difficult to note and record the reading, especially if the value is rapidly changing over a wide range of values. So they intentionally slow the rate at which the display digits changes to approximately 3 times per second for ease of reading the full number.
However, they realize that the brain can readily perceive intensity changes to a needle or plunger. So the rate of change of the bar graph is designed to react as fast as possible, 10s of times per second or more. This is likely faster than a needle moves on a traditional analog meter. As a result, there is no compromise for the user, you perceive the intensity and short duration changes, while continuing to be able to take note of readings.
For cheap-O multimeters, I've noticed a lack of consistency for the refresh rate of the display. In some cases the refresh rate of the bar graph is exactly the same as the numeric readout. In this case, the bar graph is more fancy than substance.
Newer meters are adding the ability to graph the history of the analog reading as time elapses. This almost appears as an oscilloscope reading, but is more of a data log. The graph is updated at approximately the same or lower rate as the screen values, such as once per second. This adds the ability to perceive the way measurements are changing over time, and sometimes to store the data as a numerical log or image.
Depending on the way you are using your multimeter, a bar graph or line graph can certainly enhance your ability to comprehend the fast or slow dynamic behavior of your circuit readings.
While shopping for your next multimeter, consider these graphing features and make sure they work the way you will need them to perform. It's very worthwhile to watch the online reviews and note how the bar graph changes compared to the on-display reading.