You've Supervised the Phone. Here's What Screen Time Still Does for You.

Supervision (the free iPhone setting that gives you real control your kid can't switch off) is the foundation, not the whole house. Once that hard, tamper-resistant layer is in place, Screen Time becomes your day-to-day dashboard, and finally a reliable one. Here's how the two split the work, and why you want both.

Two layers, two jobs

The locked-down setup you built (the one the kid can't undo) is the hard foundation. Tamper-resistant enforcement: block an app and have it stay blocked (even one you already approved), block bad and adult websites for good, shut the phone down every night at bedtime automatically, block factory reset, and stop the kid undoing your controls.
Screen Time is the day-to-day dashboard. The soft, flexible, parent-friendly layer you actually touch every day.

The unlock: supervision makes Screen Time trustworthy

On a normal phone, Screen Time is the pushover you remember, slow, bypassable, and the kid can just switch it off. On a supervised phone you can lock it down so the kid can't disable it. Supervision doesn't replace Screen Time; it's what finally makes Screen Time stick.

BrianFor me this was the quiet surprise of the whole project. The same Screen Time I'd written off suddenly held, not because Screen Time got better, but because the kid could no longer reach over and switch it off. The foundation underneath it changed everything about how much I trusted it.

What Screen Time still does that supervision doesn't

Daily time budgets per app or category (say, an hour of social media a day). Your MDM blocks or allows; Screen Time gives you graceful, scheduled limits.
Usage visibility, the weekly report of where the time actually went. Your control layer doesn't show you this; Screen Time does.
Ask to Buy, approve each app install from your own phone, through Family Sharing.
Communication Safety, Apple's on-device detection of nudity in Messages, AirDrop, and FaceTime. Worth knowing: this is the closest thing to "message safety" that actually exists on iPhone, and it's Apple's own Screen Time feature, not a third-party monitor. (Remember: no app can quietly read iMessage.)
Content ratings and communication limits, age-appropriate App Store and media ratings, and who your kid can contact during downtime.

Setting it up alongside supervision

Set up Screen Time through Family Sharing as usual, on the kid's child account. (If you haven't set up Family Sharing and a child account yet, do that first, it's Apple's standard setup for a kid's phone.)
On the supervised phone, set a Screen Time passcode that only you know, so your kid can't turn it off.
Use Screen Time for the soft daily stuff; let supervision handle the hard enforcement.

The honest bottom line

Don't ditch Screen Time. Layer it on a supervised foundation. Supervision does the hard, tamper-resistant part; Screen Time does the flexible day-to-day part; together they're the complete setup.

If you haven't built the foundation yet, start with the step-by-step lockdown. Not sure how locked-down you need to go? Compare the three paths.