They (SD2) all have 2 slots, the second isn't used in the non commercial version and is covered with a manufacturer installed tape. I haven't looked at that area on the "+" version but I suspect it's the same.
You can see both in this picture.
When we were testing these the second sd slot was was populated with an card used to store flight data on the non-enterprise drones. I"ve not heard of the second card slot being used for anything else on the consumer version though.
Nope, physically they are identical including the sensor and 6 vision sensors. They are really trying to sell the 3D Scan from my knowledge, which means buy the “enterprise software” (+$3500) and on top of that you have to buy the 3D Scan software at $3000/yr per drone, and to take that data to a third party and pay more to have it stitched. I’ve flown about 250 X2 flights with the enterprise software, and I’ve flown about the same with the 2+ (no enterprise software). There is absolutely zero difference in the physical flight profile, obstacle avoidance, or tracking features. I’m as confused as anyone but like every decision in the world, it’s something to do with money.