I find these "key ideas and phrases" summarized in "key takeaways" or "TL;DR" snippets to be quite handy.
If you've been through the entire piece of work already, it helps you wrap it up. If not, they're good to help you decide whether to dive in or not. Just like when you'd read a long paper's abstract + conclusion sections before committing your time to it.
Summarizing a long text into "key ideas and phrases" can also help the author see the structures and the patterns of his output, which is important for his own development, and critical if you want to generalize, go meta, and bring it onto other areas :)
If you've been through the entire piece of work already, it helps you wrap it up. If not, they're good to help you decide whether to dive in or not. Just like when you'd read a long paper's abstract + conclusion sections before committing your time to it.
Summarizing a long text into "key ideas and phrases" can also help the author see the structures and the patterns of his output, which is important for his own development, and critical if you want to generalize, go meta, and bring it onto other areas :)