That does not do what you think it does: that’s the button to disconnect from currently connected devices, not to turn off radios. Similarly, the airplane mode button above it will maintain Bluetooth.
Turning Airplane Mode on and then tapping the Bluetooth icon will fully disable Bluetooth (gray background, not white). You can also just disable it in Settings. Apple’s argument, as I understand it, is that Bluetooth and WiFi don’t actually consume much battery, but non-technical users would habitually disable them to save battery and then complain that Location Services didn’t work well. Hiding the setting but keeping an essentially useless toggle prevented those non-technical users from making their device function worse while still letting them feel like they were saving battery life.
Yeah but they forget about users who simple want to disable yet another tracking vector on their device.
To add insult to injury, when you automate WiFi and Bluetooth to turn off when you leave your home you need to manually affirm this action via a notification every time.
I created a Shortcut for that, essentially a button on my homescreen I can press which actually disables bluetooth and wifi. And when my phone is connected to wifi, mobile data gets disabled.
It's not perfect, but at least I don't have to open the settings app each time.