A car with a salvage title is worth considerably less than one without.
There was an article about this subject a while ago , in our local paper. It seems that one of the reasons for salvage title is to combat auto theft.
Basically it prevents an unscrupulous party from buying a wreck and then transfering the VIN to another car. When the article was written, Ontario was the only jurisdiction in North America that did not have a salvage law in the books, although one is in the works. It seems that auto auctions in Ontario were very popular with car theft rings from all over North America. What the people would do is buy a wrecked auto and then steal another one and transfer the VIN numbers from the wreck to the stolen vehicle and sell the car for a tidy profit, and no heat because the original VIN from the stolen car has now disappeared. Any other bits from the wrecked car are probably parted out or dumped or shipped overseas, giving them even more money.
With a salvage law in place, it doesn't make economic sense for the thieves to do this as the car isn't worth it.