I don't know if he's looking for "dynamic range". It's true it shows the short-term peaks (depending on the RC timing) so it depends on what he wants. You can't get the RMS or average but the software can convert to dB (logarithmic) and it can be used for a peak "VU meter".* And you can calculate a moving-average of the peaks (which I do routinely).
I've made a VU meter effect with a peak detector, as well as other sound-activated lighting effects.
I've also made a quick-and-easy SPL meter (which doesn't use a peak detector). It's no problem calculating peak or average dB SPL but it has no A-weighting so it's not a "good" SPL meter.
- Real VU meters don't measure peaks but they are pretty-much obsolete in the digital audio age where peaks are more important.