The biggest advantage is that it will stay in place, while the fiberglass can fall out. It costs about three times as much to install, but will giver you more r-value per volume and will reduce air infiltration better.

Carefull though. Spray foam can facilitate rot where condensation or leaks go undetected or cannot be seen through the spray on foam. Scraping that stuff off to repair small areas means a HUGE expense to find someone that will come back out to reapply it. No one wants to mobilize a huge spray foam rig just for a small patch job :( Seal the crawlspace and use conditioned air and you can insulate the walls over the concrete instead. Much better option for the long haul and energy.