Yes, it's dangerous! Since it takes away other types of sensorial experiences from young kids..it's only touch on a glass surface..
I've noticed with our young one, that he switches from one video to the next very quickly and seems to have hard time sticking to one video for too long.. as a lesser of two evils, tried putting on the TV and then turning it off after certain time (beaming the content via Chrome and controlling the timing that way)
Are their time rationing apps/systems for iOS devices? Setup timer for 30 minutes and then the device shuts off or locks? I see some paid options when searching online but don't know how well they work and if anyone here has experience with them?