sous vide it to slightly undercooked target temperature first, then roast it or put it in oven, high heat, you need flame if you want flavor the only good thing about sous vide is commercial batch processing, you cannot cook 20 bone-in prime rib roast at the same time unless you get 20 ovens or 20 individual counter for pan searing, with sous vide, you can put it in a giant water tank and cook it at the same time, reliably. and then you take it out from the bag, put the grill on max heat, the whole prime rib roast could be done in about five to ten minutes.
you can do both. or you can not sear at all. honestly if you paid for it you can throw it and a blender and make a steak smoothie and it wouldn't be wrong.