rooting your phone/unlocking the bootloader is VERY different from what people usually consider an "unlocked phone".

"locked" / "unlocked" in this regard is just about carrier locks like they are common in the US. Buying a phone through a carrier and the phone only working on that carriers network and it coming with preinstalled apps and receiving its updates through the carrier.

Buying a phone off for example amazon on the other hand will (afaik, in my country locked phones are illegal) have the phone "unlocked" -> not locked to any carrier -> only the "Samsung" preinstalled apps on it.
This will NOT trigger any KNOX protection like rooting your phone would, so your banking apps and yes the McDonalds app will work perfectly fine.