Yeah, if you use the Bluetooth toggle in control center, it doesn’t disable Bluetooth at all, it just temporarily disconnects all Bluetooth devices. If you go to your Bluetooth settings, it will still be enabled.
Tell Apple to PERMANENTLY respect the user's choices when turning BT and Wi-Fi on or off, no matter where they do it: https://www.apple.com/feedback/iphone/
And another good reason: Despite some improvement Apple seems to have made on this issue over time, the phone will still connect to "free" Wi-Fi that has no Internet connectivity as you roam around.
Apple is respecting the choice of the majority of it's users who simply want to disconnect all devices temporarily in order to solve an immediate problem. Nearly all the time, Apple's users want BT (and WiFi) ON.