I understand your method, but it probably wouldn't tell you if the circuit is hooting at 200Khz, which a scope would.
Was just going to say something similar.
"Horses for Courses" - if you're concern is getting a kit working okay then that's one thing. But if you are doing something more 'ground up' and need/want to check that it isn't singing away out of audio band (and 'using up amplifier gain' then that is something else. ( It will likely show up as a dc offset but that requires some interpretation and won't give detail).
A scope won't, of course, easily convey subtle (or not so subtle) distortions etc.
But that is why there is specialist audio kit - Audio Precision / Prism / Lindos etc...
Or solutions using less expensive audio interfaces and software. There's a role for all solutions.
On a practical note - analogue 'scopes are imo great but they do tend to have a large 'footprint' compared to cf a basic Tektronix 'scope. So if you're poking around the back of a patchbay - that's rather different from working 'On the Bench'.