Not sure if what others said was totally clear to an uninitiated person, so I will add to it (and repeat some). Sorry about redundancy.
The Greenland natives learned the rolls because they were sewn into their boats. They were sewn in because the water was so cold, to swim was to die. So they learned rolls as a way to recover from a flip.
Their boats are hunting vessel, and they use harpoons with lines to floats as their hunting means. So they never knew what condition they would be in (wrapped up in line, having the harpoon thrower but not paddle in hand, etc.), so they learned a while bunch of ways to roll back up no matter what state they were in.
Currently, they hunt with guns and aluminum powerboats, so knowing these is something they do as a way to hold on to their history. This shows up in the annual competition in Greenland (and elsewhere). There are 31 rolls (62 when you consider they need to do them on both sides). Plus other events, like races, rope games (rolls outside of a boat), and a “walrus pull” (what would happen if the harpoon line was wrapped around your boat after you got a walrus, and he tried to swim away - your object is to stay upright).
How do these relate to regular paddlers? The sweep roll many do is pretty close to the standard Greenland roll. Beyiond that, they start moving away from each other. On the whole, if you are looking to just have strong combat rolls, going the standard roll route is fine. But if you want to challenge yourself and/or celebrate the Greenland kayaking culture, go ahead and learn the rolls.
Greenland rolls pretty much require a stick (for the rolls with paddles) and lower volume kayak. The standard rolls people do (sweep and C to C) are often easier with a stick, but don’t require one.
Side note - rolls are more form and flexibility than power. Women often roll better than men.