I don't see how call and text history needs to be logged. How are they using that data to 'help friends find each other' or 'make the experience better for ever

I don't see how call and text history needs to be logged. How are they using that data to 'help friends find each other' or 'make the experience better for everyone'? Wouldn't access to your contacts on your phone be more than enough? Or even just logging who you've ever texted or called before, instead of every single call and sms.