It is deliberately a catch question to see how many have thought about the purpose of gun control.
I suppose one could ask what is the use or purpose of gun control as a question from the other direction. Is it to fight crime or does it have some other use citizens see as valid?
The purpose of gun control in history
1770s=to control the colonialists who were starting to reject the dictatorial nonsense of the crown
1860s-to prevent freed blacks from fighting back against the "Night Riders"
1870s-west-to allow the dominant crime family in some western towns to prevent armed resistance to their rule
Sullivan Act in NYC-to prevent Italian Longshoreman from resisting shakedowns by the Irish Mob which was also known as the NYPD
1934-to allow FDR to pander to those complaining about the government created violence that came from prohibition era bootleggers
1960s-as a ploy by the Democrats to stave off the claims by Nixon and other conservatives that the Democrat party was weak on black street crime.
1986-Hughes amendment-a dishonest and not properly implemented poison pill by spiteful Democrat assholes to derail a pro gun bill that was going to pass and be signed by Reagan
1990s-Pandering by the Democrats over a few well publicized shootings (like Patrick Purdy in Stockton california) as well as to implement Josh Sugarmann's strategy of confusing machine guns with semi auto sporting rifles. Also-to punish the NRA and its members for their effective support of many GOP candidates
1996-the Lautenberg Amendment-Democrats pandering to the feminist left as well as the anti gun movement
from then on its either pandering or attacking the NRA or both