It's supposed to define a "logical" name of the node for a production system, so that you can move the logical node to another host:port and still compare with historical metrics.
That is not something we need for our tests.
I think that if not defined it will use host:port as node name, which might be good enough for us, but that will mean that many nodes will be shown in the console, since we use dynamic ports.
// cc @h3nk3