They are, provided they are done correctly. One of the bad side effects of sitting so much is that one is constantly putting all their weight on their glutes an

They are, provided they are done correctly. One of the bad side effects of sitting so much is that one is constantly putting all their weight on their glutes and hamstrings, which can have some nefarious consequences when trying to deadlift (namely that the lower back ends up taking most of the load, instead of it being partitioned between lumbars - glutes - hamstrings - quadriceps). If you can afford it, a good coach is key. If you can't, spending a couple of months watching videos and drilling the lift with light weights while filming yourself to correct your posture is a good plan B.