Let's take android for example. There are legitimate security implementations like SELinux, full disk encryption but something like samsung's knox is useless outside of enterprise use and kills OS level modifications
The only reason I haven't rooted my phone is because of the Knox circuit. Rooting it trips the circuit, and it can't be reset. Once the circuit is tripped, my bank won't ever recognize my phone again, because it's "insecure".
Knox is used by Samsung own functions. Your bank app only does a root check. Which can easily be hidden with Magisk. If you trip Knox, you lose the Samsung exclusive security features baked into the OS. That's it. Google Pay and USAA both complained about root access and refused to work with Magisk hiding off. With it on, they function as normal.
Integration into Knox requires enterprise device management and a custom app.
Huh. I'll have to give it a try then. My prior phone, which had been rooted, wouldn't work with my bank, and my bank claimed it was due to the Knox circuit.
When Knox is tripped it sets off the root check. Your banks misleading statement is due to their own confusion. Knox is no longer active so it can't guarantee there is no root access. The OS basically says it's untrusted/insecure due to lack of Knox and always says it's rooted regardless of that actually being true. You can hide root for all apps that check. Do note that while you can return the functionality of third party apps, Samsung baked in apps can be hit or miss. It's a game of cat and mouse. I speak from experience.
Additionally here are some other conversations about it: