As I said, those are all 1st party applications. I don't see it anywhere being OS-wide. And what's "smartlook"? Do you mean Spotlight? I haven't seen any AI in Spotlight, but I also haven't installed (the janky) Tahoe yet.
On MacOS, at least for now, AI isn't prominent at all. I've been using an M4 Air for a month before I remembered that Apple Intelligence was a thing and had to google how to use it. So far it only seems to be partially available in 1st party Apple apps which I don't use anyway.
There's usually not enough interesting things happening on the screen to maintain a child's attention, it's mostly just conversations. They might look at the screen occasionally but are unlikely to pay much attention.
I mean, just because it happens fast or in an unnoticeable way doesn't mean it doesn't happen. If somebody vaporized themselves instantly it's still suicide. Sure, people would probably accept the fact that their original is being killed for convenience, but the fact stays.
Because technically, it's a scanner + printer and not a mover. It's just that the original is deliberately destroyed every time (unless something goes wrong looks at Miles).
IIRC, it's even mentioned that people going through the transporter are cached. Like, they store snapshots, so you can compare the changes between older you and newer you. You can also store a person in buffer digitally, meaning you can copy and print as many as you want.
Hopefully it doesn't suddenly evolve inside that glass.