What application are you referring to when you wish to not utilize the seatbelt to me would be important.
Doing the driveway with plow or puttering around the yard at 0.2 Kph I do not use it. But if I run to a buddies 2 kilometers away I certainly do...it takes about as much time to put it on as it does for the fuel pump to energize.
When me and momma bear we never leave ours off...why, a neighbor (whom we do not ride with) older couple, overrode a small dike. The thing (Polaris) turned turtle on them on impact with the ditch. She got ejected from the machine. He came out with pumps and bruises...she crushed her pelvis and at her age may never be the same again.