Can't disable Orbi guest network

I'm on firmware 1.8.0.6. Even though I disable the guest network, and orbilogin.com confirms it's disabled, it still shows up and works. Not only that, but you can see all the devices on my main network, even though that option is disabled.

Effectively it's my main network with an easier-to-guess password. Is there any point to using a guest network, beyond not having to give out the password to my main network?

Thanks for your help!

Brian.