Diagramming Fun?

First, I do actually have 3 sons. Sammy is in pre-K and doesn't have the patience to sit with us for very long. So here's a little bit on Sam doing his thing. Coloring a zebra and working on his letters.

We have been using First Language Lessons for 3 years now. I do love it. It's very repetitive which is a must for my boys. However, we've been diagramming sentences for weeks now. Each time they learn a new version of an adjective or an adverb, there's diagramming. As an adult, the only time I've needed to diagram a sentence is when I'm teaching my kids to diagram a sentence. It seems utterly pointless to me. Just curious if anyone has used this 'in real life'?