One thing 7-segment displays does better than LCDs and OLEDs is refresh rate. They can have a very high refresh rate, and this can help detect noise or variatio

One thing 7-segment displays does better than LCDs and OLEDs is refresh rate. They can have a very high refresh rate, and this can help detect noise or variation in the signal. I have two lab power supplies, one with a 7-segment display and one with an OLED. The 7-segment one allows me to easily see issues with the circuit due to the refresh rate, such as unwanted oscillations, which can be completely masked by the comparatively slow refresh rate of the OLED. I won't necessarily see each value, but I'll notice a slight blurring of the least significant digit for example.