Aside from a voltmeter, are these useful? If so, how are they useful?
Only if you make your own drivers.
I have been modding flashlights for 10 years+ and never needed one because I only buy drivers and build them in.
However, you need a machine that goes “ping”.
I have a oscilloscope, I use it for different tasks. Never needed to use it at flash light work.
What kinda stuff do you use it for? Trying to give myself a reason to get one
Tune and repair communication equipment.
i mostly use my o’scope to measure ripple and spike voltage
Some time to see the waveform of my signal