Yes, that is correct. The consensus is that it seems to be working perfectly fine with the M1 Pro but not the M1 Air. Connecting the Air to a 5V power source doesn't seem to trigger the charging logic, and the Air appears to require Power Delivery with at least 9V/2A (aka 18W) to take any charge at all. I obviously haven't tested this myself yet but I have no reason to doubt
@bondr006's findings.
I've also watched the two videos above, as well as similar other ones, and the 2018 Pro seems to be subjectively faster thanks to its 120 Hz display despite its slower SoC. That could very well make a huge difference in the long term, after all subjective performance is all that really matters to me. I am also taking the 2020 11" iPad Pro with 6GB of RAM and double the storage into consideration as that is available for $609 refurbished and could potentially last even longer thanks to its 120 Hz display.