Other things using the 2.4GHz spectrum might have malfunctioned because of that and the users would have had no recourse. Even if you can, you should not do this unless there are no neighbors within range and you can ensure that you will never put anything else on 2.4GHz near it.
Also, I do not believe iOS ever added support for 40MHz channels on 2.4GHz. That feature never should have been added to WiFi. It causes headaches practically everywhere it is used.
Could probably do a scan to tell if 40MHz or 20MHz was better, but practically these devices are not used in areas with neighbors. The cool part was that our noise floor was great.
> It causes headaches practically everywhere it is used.
It really does - we got a few complaints that the latest iPhones took twice as long to sync as crappy Android phones. Not enough that I would choose differently on the next one, but something to consider.
The other wonky thing was that the usual channels 1/6/11 become 1+6 or 6+11, always up against guardband limits, but reducing power impacts bitrate across the entire bandwidth. Channel 4+9 didn't have this issue but overlaps with all 20MHz channels. I hear the newer WiFi specifications are better at managing this.
File download time decreased by about 40% on Android but not at all on iOS - turned out at the time they only supported 40MHz+ on 5.8GHz.