There are several aspects at work:
A stock engine/trans combination (i.e. stock heads, valve covers, and oil pan, and toploader or T-10 transmission) can be installed or removed from the top. My Canton road-race oil pan comes close enough to the crossmember, and it’s deeper by enough, that you can’t tilt or lift the engine/trans combination such that the oil pan will clear the crossmember on the way out. Some aluminum heads are taller than OEM iron heads, and this in combination with oversize valve covers might also cause problems. So depending on your engine setup the ability to go in and out the top could be a non-starter.
Another thing is that the engine/transmission combo is over five feet long, and it has to come out of the car at about a 60 degree angle. This means that you need at least four feet of headroom above the car, plus room for the hoist chain and arm. Assuming you start with at least the nose of the car jacked up, you may need more than eight feet of headroom, floor to ceiling, and some garages don’t have that much (or that’s all they have).
A last thing is the creep factor of pulling a 500 pound (or more) assembly that high in the air above your car, supported by a marginally stable cherrypicker. On mine, the lateral wheel spacing is only about five feet at the rear, and about four feet at the front.