Is it worth the gambit grind?
It honestly depends. Do you like bows? Do you like a good grind? Are you good at hip-firing? If so then yes. To be honest I have not gotten the bow, but I can see some drawbacks. For example, hip-fire headshots are not easy in the first place, especially on a bow. I wouldn't use it in a boss fight, because who uses a bow to damage a boss? And in PvP it seems like it would be hard to activate the perk but the draw speed bonus might be good. So it is very situational. If you like PvP, bows, are good with hip-fire accuracy or just want to full your collections, then I would recommend it.