I don’t understand what having an off button has to do with it. If Lucid wanted to permanently store last known tire pressure in the app, they could easily do that without waking the car. They already do keep that data for a short period. But then they override it when the app wakes the car and asks for the sensor data again.
Your Mercedes can’t be giving you current tire pressure, because tire pressure sensors require the tires be in motion for a bit before they work. So that data is whatever the car last reported. If someone slashed your tires overnight, the app isn’t going to read that.
Trip data is even easier. Have the car report the data to the app and store it. If the car is asleep, there’s no way that data can change.
Getting a bit more complicated, I think Lucid could find a subset of live data that wouldn’t require a “full wake” such as SoC. They could also allow unlocking, opening the frunk, etc without having to wake the car fully. A small set of commands. Tesla did something similar a while back, and it made opening the frunk or turning on climate from your phone much quicker and more consistent.
That way, the car would not fully wake every time you launch the app. It could just communicate for those limited things until you actually open the doors.
There’s no magic to a physical on button that can’t just as easily be accomplished with an unlatched door or a press on the brake pedal.