I’m just guessing, but I think since it is a keyboard, it has to be within a certain distance of the computer that is generating the signal. It has nothing to do with wifi. Other than that, it’s just 2 different bandwidths for the signal. the 2.4ghz is a bandwidth that is used by cordless phones, so if you have a phone in the house that uses that bandwidth, there could be trouble.
Bluetooth signals travel about 8 feet. Or at least, that was what the manual for my bluetooth printer said. And when you think about it, your bluetooth phone isn’t going to be more than a few feet from your earphone or your car when tethered to them.
But bluetooth and 2.4ghz both require that the keyboard be within a few feet of the computer that is generating the signal, I expect. And they have nothing to do with wifi. That’s just an educated guess, though.