Okay, but the art is dancing around an actual important technical question without answering it, even though it would take far less effort to do so.

I'd refer you to the top-voted comment from @ daturkel. Because of the psychoacoustic models used for lossy audio compression (and, in particular, the "masking" effect) listening to these delta signals won't give you useful information about the compressor's accuracy.

I disagree. It gives you information you have to treat carefully, but it is useful.

Especially to compare different bitrates. I'm not even sure what bitrate this used, maybe 128 like the example files?