2 Degree offset rims basically move the contact patch of the tire outwards. Typically found in many Tamiya kits, the offset is put into the rim primarily for clearance issues with suspension parts. A secondary benefit is that the contact patch of the tire moves outwards giving the car a wider stance - which can improve stability.
They can be used on most cars as long as there is body clearance. I tried running offset rims on an FK05 a couple years back and the tires rubbed the body.