Variable Speed Limits

Really what is the point of the variable speed limits in Melbourne? they slow down already slow traffic to below the speed of the limit ie, I am driving in a 100 zone and we are coming passed an on ramp traffic slows to 80 just because they are all inept merging into traffic (I can almost live with that) but instead in Melbourne that decide to use the variable speed limit to change the limit to 80 and as a result the traffic slows to 60. When I was in the ACT they didn't have this variable speed limit and we all did just fine. Wouldn't the congestion be elevated by just leaving the speed limit alone? And if drivers were to have a bingle they would be off the road further elevating the congestion as well as providing needed jobs for Insurers and smash repairers.