I know AUS has snow... was just kidding...
you don't need much speed to loose traction if you are on a road where you need chains...
but then again I don't know what the rules there say when you need to use them
when I was in the US I was like

I went to Seattle (near the Rockys for those who don't know) in winter and it snowed a little (atleast I thought it was a little) and everybody stoped and put chains on their cars... and I thought you are damn crazy! those chains will make you LOOSE grip on a fairly normal (only wet from the snow) road.... and yes I was right... there was a traffic jam and we stopped (we had no chains on the cars..) but the Idiot behind us did not stop fast enough (and did not leave enough space behind us but that is a other story) and drove into the back of the nice Volkswagen Carmangia... with his damn car with chains on...
but he...
I know you are right about the main place to put chains on a car. but you can't tell me that when driving on snow you don't benefit from chains in the front...even with RWD cars