I've fallen out of the habit lately, but I was hitting the 10k target for a while. I have a sedentary desk job. So chores and playing with my kid got me up to about 3k. Then I'd walk for an hour during lunch to get another ~7k steps. Walking for an hour every day is fairly substantial commitment. I mean, it felt worth it. As you said, it's a huge productivity boost. I'm probably more productive walking 1 hour and working 7, rather than working a sedentary 8. It's not always easy to make that time in your day though.
I added the backstory, because I'm not questioning the value of the habit. I'm just always curious how much time people are devoting to walking when they talk about 10k steps.