The app operates independently of your phone. Start music, turn off your phone, then control it from your iPad. Reduces battery drain.
That said, the app is so terrible now that I avoid it and use Airplay. Will never buy Sonos again and glad my newest Sonos is now several years old. Bought a JBL Authentic and it works well with Airplay and is cheaper than a comparable Sonos.
Unless you're on the hype train "all things AI". It's always surprising how many real life problems do not necessarily need a solution based on the buzzwords du jour. All things blockchain, all things microservices, all things as-a-service, all those came and went, washing off the bubbles and leaving behind the (fewer) worthy pieces.
Buzzwords aside, I'm pretty sure the MTA's license recognition here is plain old ALPR, of the kind that's already been in use for municipal fare/toll enforcement for ~15 years.