It's used for the cluster's IsAlive check. It takes minimal resources. It wasn't there on SQL 2008 or below because it was only introduced in SQL 2012.
Thanks for reply!
Well, that explains why I do not recall such thing on the Cluster I managed before.
Do you know any useful link I can use for further reading?
Also, my RedGate Monitor tool (and Management Studio) have a different opinion, lol ... they keep flagging it as intensive query ... I wonder if I can filter it on SQL Monitor and exclude. But I was afraid of flagging an important stuff ..