Let me see,

:
SHTF after a year half the people had died no law or order, you are hiding and only gangs and starving out of mind people are running the streets or suburbs, you and your group manage to prepare and have enough water and food for some more months and you are waiting better time to come out.
Then your position is discover by a gang of 5 to 10 willing to kill for anything and charge your location trying to overrun and kill you and your family, your group and you are just 3 to 5 adults,
So which “practically” you wanna choose:
a) Jump out of your hiding and fight them using your non-lethal weapons (bats, batons, pipes)
b) Wait until they reach the killing zone and shoot at a rate of 4:60sec lethal 100gr velocitip or xcalibur type arrows at 400 ft/sec. (if any come across I would use an axel or spear for a final close quarters combat )
similar apply in a bug out situation, the crossbow will alway let you keep distance between you and the zombies an is legal in UK so is a no brainer in this nazi country.