Aren't users breaking their acceptable use policy (AUP) with the EV OEM when they do this? Legally speaking, users are giving you their username password to see their vehicle stats for personal consumption, but you are also making them sign a T&C that says it's ok for you to sell their data to B2B operators for revenue? Sounds fishy to me.
Should it matter? If you bought the car and have access to your charging data, you should be able to delegate that access to a third-party if you want.
How is that? TeslaFi.com has been there for ages. Many others exist. And Tesla actually improved API access over the years (can now use tokens vs. having to share your account password with the app).
This sounds a lot like abetterrouteplanner, which already uses the Tesla API. They even get daily supercharger availability information to handle any temporary closures.
A lot of people in the community use Teslamate and Teslafi. The Tesla unofficial API is actually pretty good too.