Gaffer tape is traditionally used in the film and theater industries by lighting techs (Gaffers) who use gaffer tape to secure lights and conceal wires across floors preventing tripping hazards. Brighter color gaffer tape is also applied to stages as spike marks helping performers and stagehands find their marks - even in low lighting. Its easy to tear so the right size piece is always available.
Gaffers tape is now widely used as a duct tape replacement. Unlike duct tape, it's highly removable from most surfaces and a better choice most anywhere you would typically reach for duct tape. You'll notice the benefits right away as you tear the first strip off the roll.