In Canada, all individuals seeking to legally possess firearms for personal use must acquire a Possession and Acquisition License to legally own them. It is a criminal offence to be in possession of a firearm without a license, regardless of how you came into possession of the firearm.
A PAL/RPAL can be an asset or a requirement for some careers or professions. Security and law enforcement agencies in particular require a gun license to apply to their positions.
Some of the reasons to own firearms personally in Canada include target shooting (sports or leisure), hunting (pest control or subsistence), and collecting (historical or interesting designs).
Self-defense is not a valid reason to possess firearms in Canada, and it is a criminal offense in Canada to be in possession of any object (regardless of its nature or design) for the explicit purpose of self-defense.