You’re right. There’s no real downside, and I do hope Lucid adds it eventually. I just would caution against thinking it will be helpful in any vandalism or accident situation. You may get lucky and end up with footage that helps, though, so why not have it?
I also think Sentry is at least a slight deterrent to casual vandals. In fact, we may be benefiting on our Lucids even without it, as some may assume any modern electric car has it.
If there was one downside I found with my Tesla when I had Sentry, it was battery drain. On a day-to-day basis, it was no big deal. But once when I left the car at the airport for ten days while vacationing in Hawaii, I had to turn Sentry off, because it was draining 10-15 miles a day off my battery. And at that rate, I would not have been able to get home after the trip.
So when I needed Sentry the most (busy parking lot with a known history of issues for several days), I couldn’t use it.