I've used the remote exactly one time in 6,000 miles - To precool the car when we had a big wedding cake sitting in the back. Yes, you can reliably charge the car with any EVSE you like . . . . so long as you aren't using the remote
The remote can be used to either preheat or precoool the car for 30 minutes so long as it's connected to the EVSE for power. It can also be used to set the charger ON/OFF times, like you would want to do if your electric rate goes down at a certain hour so you can charge overnight using the cheaper rates. I doubt it gets used much at public charging stations
Other than that, it doesn't do much . . . . Oh, you can check the rough state of charge without going out to look at the 'gas gauge' in the car, but I suspect most of us don't use the remote too often - Certainly the cold weather guys are probably using it to preheat in these cold temps
It's certainly nothing like you would expect from a BlueTooth cel phone app . . . . .
I'm just guessing that the car is set up to recognize the pilot signal specific to an 8 amp L1 or a 16 amp L2 charger and any EVSE which doesn't give exactly that pilot shows an error on the remote . . . . just a guess mind you. I'd bet now that Mitsu is aware that this issue is ticking off a number of owners, this will be corrected in the next software upgrade
One of the things I really LIKE about this car is that most of the functions can be greatly modified just by making software changes - When tech guys like you figure out how to do that, the car will be readily (and cheaply) customizable
Don