I and several other people would disagree that there is NO reason. Both the mobile charge cable at the maximum 40A and the wall connector at its maximum 80A have significant heat. Running them at a bit lower current keeps them noticeably cooler. And since heat and especially heat cycling, where something swings by many degrees from cold/hot/cold/hot every day, is a main cause of degradation and material stress in electronics, there is some thought that your charging equipment can last longer if it is not getting as hot every day. Depending on how far you drive, if it takes 5 hours to recharge or 3 hours to recharge while you're sleeping, that probably makes no difference to you, but you can likely help your equipment last longer by not stressing it as hard every single night. Occasional use at 40A is still fine, but for daily use, a little less current will probably help it last longer.