Well, if you're looking to save your Internet connection bandwidth or data usage then you SHOULD enable it - but only for local machines.
In this mode it's essentially a domain-free Windows Server Update Service: your PC will download the updates when possible, then seed those updates to other machines on your network, this will use slightly more local bandwidth (of which most people will have a Gigabit) and less Internet bandwidth (which most people will have only around 20Mbps of bandwidth for).
If you disable the whole local seed update system, all machines will then use the Internet Connection ONLY for their updates; if you have 5 systems in your house, that's 5x more bandwidth and 5x more data used.
Think smart on this one, it's a brilliant piece of tech.