As far as my understanding, some states are starting to require you to have a side arm when bow hunting. The reason I'm told is safety. Sometimes the animal is not down when you walk up to it. I used to talk to someone who did a lot of bow hunting and he said he would always have his side arm drawn when walking up to the deer he shot.That's an impressive weapon. I'm unfamiliar with Grizzly hunting - Does the law provide for carrying a firearm like that while you're bowhunting, or do you need a different license?
I'm in Canada, and I'm sure the laws are different here than in the US.