This is great and has an awesome level of detail on information gain. I have found decision trees really useful for getting a feel for what features in a dataset matter and trying out different max depths on trees to get more insight into the data.

I wrote an article earlier this year on how I use decision trees to classify players for daily fantasy sports into different groups that people may find useful https://medium.com/@bmb21/why-is-caris-levert-projected-for-...