I'll tell you what I'm in the military and after Basic Traing I got out about 20 pounds lighter but my strength was actually up.And I'd have to think it was from those pushups all the time
I use them to warm up on chest day.
Two or three sets until failure – with my feet up on a bench. Up as fast as I can and a slow negative with a pause at the bottom.
I think it helps warm up the chest, delts and tris nicely.