Normally, any dedicated ranged unit is entirely dependent on others if the enemy closes into melee range. Not such with the Thorn Watch. These crossbowmen have also trained extensively with longswords and while they aren’t a match for most, at least they won’t simply disintegrate if someone can get in melee range.
The Thorn Watch Unit Box gives House Baratheon commanders who are backing Renly a versatile ranged unit for their army. Skilled with crossbows that can puncture enemy armor with ease, they are also able to hold their own in melee. Plus, they have ways to break away, meaning they can once more ready a deadly hail of bolts upon foes. With a Thorn Watch Sentinel attachment, the unit gains staying power, as well as more freedom of movement on the battlefield.