2012 Traverse with V6 requires spark plug replacement. Why does the intake manifold have to be removed to replace them? What are the risks if they are removed/replaced without removing the manifold?

 

I have a 2011 and am also looking at replacing my spark plugs. In the next few days I’m going to replace the front ones and look over taking off the manifold cover vs not. Seems to me the risk of not removing the cover is loosing some bits and pieces if you don’t have a magnetic tool.