I have the F800 Pro so what I talk about is in reference to the Pro. As far as I know, this may not work on the F800 as it does not have cloud features.
Vehicle speed is determined by the GPS and not the internet. You have that regardless.
When you connect to the internet, it’s for the cluod features. Connecting to the internet is different from connecting to your phone.
When you connect it to the internet, you can then register your device. When you register the device, you can now remotely check on it, providing that the dash cam is still connected to the internet.
For instance, you register your device and set it up. Good. Now should I ever get in your car and drive it for whatever reason (you let me drive it or I stole it, etc) you can now track the vehicle via GPS and see the direction it is heading. The GPS refreshes every 10 seconds so it should be fairly accurate. On top of that, you can get the driver speed and any impact notifications should your camera report any. You cannot use Live View remotely to see someone drive. Hopefully this will come later on. You can also set boundary notifications so if you lend me your car and I drive x miles away from you, you will get s notification that I have passed the boundary that you set ( should be anywhere up to 600 miles if I remember correctly).
Hope that’s of some help.