It's about helping them learn the value of money, too many young adults work hard but waste all their salary on booze and socialising until they get to mid 20's and realise that a deposit for a house is in the region of £20,000.
I'll be encouraging my children to save for their futures and not to live beyond their means but I hate to be old knowing they'll pay an inheritance tax on my wealth so intend to pass it on to them wherever I can and if taking housekeeping and giving it back to them will help then it seems an obvious choice
Jeez. You should be blowing all your cash on booze and nights out when you're in your 20s. Save the boring stuff for later years.