I've been researching new wheels for my Jeep Grand Cherokee. In todays world, the more + offset you have means the tire is moved closer to the centerline of the vehicle.
The closer you get to 0 offset, or - offset, the tire is moved farther from the centerline of the vehicle, thus moving out toward or past the fender well edge, which may cause rubbing issues.
Offset is very important, especially when carrying a load.
Most tire websites will give you a rim width range that each tire is rated for. My tire size 265/60-18 are rated from 7.5-9.5" rim width. My stock wheel is 8" and has a +56mm offset.
I'm sticking with a 8" wide after market wheel and the one I like has a +30mm offset. The tire will move out about 1 " from stock, the max I want to go.