I've definitely found fasted running to be a very handy thing - simplifies a whole host of details. I was mostly running fasted through the last few months - up to 20km steady pace.
This was the unintentional impact of doing a dietary reboot where I switched from very carb-heavy plant-based to very low-carb local animal products (including fat). Without really meaning to, I guess I become "fat adapted" and then more metabolically flexible. That meant that I'd wake up and instead of going for toast first thing, I was "full" from last night's dinner at 6pm. So I'd just run. And it felt great.
I have recently adapted to fueling before again (sometimes) because I'm in a marathon training plan that I'm finding is really amping up how much fuel I need, overall, and fasting meant shorter eating windows during which it was just too tricky to get enough food in me.
But I like to keep the option in my back pocket!
Great piece - thanks for sharing this.