Is crying good for your baby's lungs?

Friends and some random people I just met always say that crying is good for our daughter, Mackayla's lungs.
Honestly, I don't believe that at all. I don't see any connections between my crying baby and her lungs.

I think babies cry for a reason; they might be hungry, their diaper is wet, they feel uncomfy, they are in pain or they need some attention, or sometimes they don't even know what they want, but there is something. They may need to vent, suck, or just be comforted.

Of course I let Mackayla cry, but then I come to her and check on her again. I don't think that if you let your babies cry too long is good for them physically and emotionally.

As you baby cries, her arms and legs tighten, her mouth gets dry, her lips start to turn blue, her lungs probably ache, her blood pressure goes up, the veins in her head may swell and even break, and her blood oxygen level starts to go down, not up.

So, crying is good for your babies?!?! NOT TRUE!