As other's have said, a lot of people buying the Rebel don't need 4x$, but they like the look. As someone with a Rebel, (bought with ~260 miles from the stealership, either about to, or just, broke 78k after ~5.5 years), My rebel has been in 4x4 mode ~4 times. Once when I got stuck helping a buddy clear his garage (Detached off the back yard, and it had just rained), once leaving an AirBNB in the mountains, misjudged the curve of the driveway, so got the Hemi/cab over the bend, and the ass was basically floating, once during some testing, as a buddy couldn't believe they would sell a 4x4 with only Low and Lock, and I think I got stuck one more time. So total 4x4 time in like 1700 engine hours might be 1 hour (had to go down the mountain the AirBNB was on in 4x, as other people were trying to leave too, and it was a one lane, so I couldn't stop to put it back in 2x mode until I could pull off somewhere.
Almost used it once or twice when the weather was meh, but the '18 rebel for some insane reason doesn't have 4HI/4Auto, so couldn't do highway speeds in 4x, and didn't "need" 4x mode.