You don’t absolutely need a metal toe guard for your snowmobiling boots, but it can be a plus. It provides extra protection for the front of your feet and makes you feel like you can take on anything you might find in your way, and you probably can! It’s almost as if you were wearing a piece of armor. The obvious drawback, of course, is the augmented weight that comes with it, that increases the heavy feel that some already weighty boots can have.
All things considered, it’s really up to you. Not having one is not a deal breaker and you can enjoy your time all the same, but if you feel the need of having that extra protection then by all means go for it!