I am not a battery scientist, but from everything I've read, using the supercharger should have no effect on battery life long-term. So long as it's kept within certain charge and temperature ranges, the only thing that counts down the lifetime of the battery cells are actual charge cycles, which you can pretty conveniently measure in miles of normal driving use (expected up to 30% loss after 100K miles, and the 5+ year old Roadsters actually averaged just 15% loss after 100K miles with older battery tech). The supercharger doesn't do anything that would reduce that life expectancy; it communicates with the battery about its health and charging speed begins to slow progressively after about 50%.
Not really true, there's many variables including how 'full' you charge the battery, how much you discharge it, what the charge and run temps are, it's not a simple equation.
For example, if you don't charge and discharge the battery fully, you can get many many times more cycles out of them.
Charging quickly does release more heat, which can reduce the lifecycle of the battery, but there are workarounds to minimize this.
I am not an expert at battery chemistries, but I work with EV charging systems quite a bit.
What part is "not really true"? Despite only writing three sentences, I touched on every factor you just mentioned. The Tesla charger and battery system keep the battery within the safe charge and temperature ranges at all times, even when supercharging. It has active heating and cooling, even when the car is turned off, and will neither fully discharge nor fully charge the battery pack even if left unattended. There's nothing inherently damaging about temporarily charging faster AFAIK as long as you control for all those variables, which Tesla's tech does.
Truth is, the type of use these batteries get isn't well understood yet. No one really knows the long term effects, we can make educated guesses but until a lot of them are in the field with average use cases for years, we won't see much of the nuance.
Which are two of the very many variables. His point that a certain number of cycles is consistent is not correct, it's affected by drive and charge style, and a lot of variable inherent in the design of the system.
