I know Microsoft took a lot of flack for including this in Windows 10, but if done right, it's a win-win. Why? Well, if you have 50 computers all downloading the same update from the internet, you're using 50 times the bandwidth necessary. If after one computer got the update, the other computers in the network could pull from a local source, you reduce the bandwidth required for both Avast and the customer.
I can see that this might not be helpful to everyone, so making it optional would be good.