Wrong - It is a lot LESS strain on the starter
to spin up the engine without compression. Then if memory serves me correctly, because the angular momentum of the engine is conserved (simple physics), the starter has FAR less work to do when the compression lever is dropped. If it is not easier on the engine and starter, why is this the preferred method when ones batteries are low? That logic alone tells me that it is much easier on the starting system. If you add to that the fact that when the engine spins in decompression mode, it begins to pump oil to the vital engine bearing surfaces. That reduces friction and is better for all of the engine bearing surfaces than just cranking with compression. The usual starting method is harder on the starter and harder on the engine. As I understand it, most engine wear occurs during the first few seconds or minutes after starting due to lack of immediate bearing lubrication.