The device performs involuntary "CSAM" scans (where "CSAM" means whatever any given nation's intelligence apparatus doesn't like). If you don't believe it, just look to what they've done to their customers in non-US regions. Or that Mac phones home about what programs you run.

App review is meant to enforce Apple's payment rules as much as anything. They don't and can't catch everything.

Strong sandboxing, granular permissions, and remote kill switch (that can be disabled) can do effectively the same job. It just won't earn Apple gobs of racketeering money.