Let's assume you have a 25 Mbps plan, of which, you will ALWAYS have within 10% of that 25 Mbps bandwidth. The magic here is virtualizing the radio network and recycling frequencies within the density of the network. It's basically oversubscription running on the radio network and not your internal network.
So since little to no oversubscription is running on YOUR PURCHASED BANDWIDTH you can have increased local network speeds! Keep in mind, the more devices you have on your internal/local network the more your internal home bandwidth is depleted and with it, your speed will drop!