Discursive writing too often demands more attention than the content requires. Why go on and on to no point?
A few telling words will say more than a paragraph of rambling.
Say what needs to be said, then stop talking. Brevity is the soul of wit - Brevity cuts to the chase. Verbosity strangles meaning with ancillary details that confuse the subject and ruin jokes.
Oscar Wilde said the secret to being a bore is to tell everything you know.
The Roman Poet, Horus, advised young writers, "Don't lose your readers with beginnings that refuse to start". He might also have added: don't lose them, after
the beginning, by taking too long to get to the point.
Good advice is easier said than done.
Saying is also easier than writing.
Talk meanders from this to that - usually without completing any one thought and with little attempt
to organize thoughts into coherent sentences.
Vagaries are hard to remember. Most of what is said is forgotten as soon as it's said.
Writing sticks around.
Writing doesn't easily tolerate vagary. You can
write nonsense, but you have to put your nonsense into comprehensible sentences. If you don't do that, your readers will have no certain understanding of what your nonsense is about.
Writing encourages responsibility, or it should.
If you write something stupid; there it is in black and white; mocking you. Fortunately, rewrites allow you try again, and again. If you still can't manage to get it right you'll at least realize that what you're trying to write about isn't writeable. Your thought is confused.
When thoughts are clear, writing is easy.
Even silly writing requires coherent thought. I think this useful requirement of writing doesn't get nearly the recognition it deserves. The most foolish parts of foolish ideas are often exposed by the simple discipline of writing them down in grammatically correct sentences.
I try to keep this model in mind when I write:
Start with an intriguing example of what you're talking about; Expand, amplify, and explain; Close with a few final words that summarize the topic; Use short straightforward sentences; Get to the point; Add no more detail than truly needed; Respect the time and intelligence of your audience - Less said, the better.
That's what I try to do - whether talking or writing.
Sometimes I succeed.