I'm thinking strictly of things like mixers and junction boxes. I take your point about DSPs and other system clocks (and am trying to figure out if this is an issue on a hybrid DSP/FPGA/discrete device right now), but in areas like live sound engineering your main enemies are things like ground loops, crosstalk between mixer channels and whatnot. These are installation issues rather than product development ones.
Seems like a portable, precision FFT analyzer would be more useful. The ability to measure frequency response, harmonics, cancellation, distortion, noise, etc. make an engineer's job so much easier. Frequency information is far more important than timing information.
What benefit does an oscilloscope have over meter+ears when resolving ground loop or crosstalk issues? Time domain information doesn't seem terribly useful.
Knowing whether a hum is 60Hz or not tells you whether it's a ground loop or some other problem. For crosstalk a lot of mixers have a 1khz sine tone generator. It's useful to be able to verify that you're dealing with a particular frequency. You are not always able to rely on your ears to the extent that you'd like when you're in the field, since the environment where a PA is being set up can be noisy as well.
This device has a few other tricks up its sleeve as well as a basic 'scope; it also does FFT, phase metering, and operates as a voltmeter. I'm not suggesting it's the ultimate device of its kind, just pointing out that there is a class of people for whom having this functionality in a highly portable package would in fact be handy.
Oh, and the protocol sniffer means you can test MIDI output from a synth or sequencer.
