Interestingly I never really thought about it until this post. A long, long time ago (maybe Wordpress 2.x era?) I used a desktop app that would connect to the WP API. Nowadays I usually write in Google docs. Not because I don't like WP's editor, but because by by using Google docs I can work on it a little during my lunch break at work, or on my phone while in line at the store, or when in the car waiting to pick up my kids. Then I just copy/paste into Gutenberg and it usually preserves all the things I care about - bold, italics, links, headers.

If I'm at home and I think I can whatever I'm writing in one shot, then I'll just use Gutenberg.