Until I find out otherwise, I'm going to consider this a favorite feature:
Our Gravity is in for service right now, and earlier today I got a "critical alert" on my iPhone (these are the ones that loudly go DUN-DUN-DUN even if you're on silent). The Lucid app showed an alert "Impact detected! Tap for more information" (or some similar wording). I'm hoping this was a false alarm from something at the SC, but it's a pretty cool feature to get a critical alert if there is, in fact, a collision (while parked, or while another driver is in the vehicle).