A common benefit is
-you can unbolt your driveshaft from the flange at the tcase (with the sye, a flange is bolted to your tcase output shaft, and your driveshaft is now bolted onto that flange) and limp home in fwd if something should happen to your driveshaft without your gear oil spilling out. You then need to have a drive shaft that has the slip built into it.
-depending on lift height, a double CV joint may be needed to help with driveline angles and a sye makes it easier to attach too rather than having the weight of the double cv and shaft resting on the tcase output shaft seal which can cause leaks.
-you can use a driveshaft emergency brake kit with a sye.
These are what I can think of at the moment.