Most chargers aren't plugged into a place where you can conveniently lay your phone down 8" away.

I'm inclined to say your opinion is wrong.

(/s, kinda)

After taking a cursory look of where plugs are located in my house, I think I'll have to put my phone on the floor when I charge it if the cable is only 20cm long. 80cm is the minimum to be able to put the phone in a table while charging.

Edit: disregard that, the plugs are 30cm above the floor so my phone would be hanging by the cable.