Assuming nominal voltage of 3.7, that’s about 60Wh. For comparison, the 14" MacBook has a 70Wh battery.
That’s not good battery life but it depends on what kind of usage they’re assuming with that 7H number. I’m not sure a MacBook runs that long under high load. If it’s 7H on a heavy load, that’s respectable.
Edit: not sure what class of device is the best comparison here. Laptop? Tablet? Phone? 🤷
It is increasingly difficult to use X without an account. Not sure what the signup process is like nowadays. IIRC it used to require phone number verification in the Twitter days, but perhaps Musk relaxed the requirements in order to better pad the usage stats with spambots?