In regards to why someone would ever need 72A charging... #1 is medical needs. In my case I my Dad had a sudden serious medical issue that required several round trips to the Dr. from a rural home. You do anything for family. Fast home charging allowed the MX to be more than a novelty, it was the right car for the job. To that I add, I almost forget its electric. For the price range of these cars, it better do something terrific, and I count fast charging in this category. As recent as the prior week, we have a Oncology Dr. friend that intentionally comes to my house to charge when her needs are urgent, for similar medically required frequent long distance travel.
#2 is business. Several times things just come up, and our line of work requires us to be places at convenient times to clients.
Further, when Tesla was awarding HPWC's for referral credits, it was one of their best moves. Help take electricity load off the SuperCharger network. The HPWC I earned helped me put in a 2nd HPWC. So that I can accommodate situations where our Dr. friend needs help.
#3 is convenience, certainly. I find it an unfortunate call that M3 owners also don't have this option. Where high mileage users could take load off of the SC network, with faster home charging.
To those who seriously would benefit, I highly recommend installing the infrastructure at home to support the 72A+ charging rate. Just can't fathom why high home charging options were dropped from the S line -- which is advertised as the flagship vehicle.
-TechVP