I switched to weight lifting, walking a lot and some kettlebell training for weight control after running for many years. Running is great but in my case resulted in joint and back problems.
One surprising thing about walking vs running is that running doesn't burn all that much calories compared to the effort it requires. While I can integrate walking into my daily routine (15-30 minutes in the morning, at lunch time and in the evening), running needs at least 1.5-2 hours per day.
> most of the calories burnt are just so the body can maintain itself (basal metabolism), not from the exercise!
When reporting how many calories are burned through exercise, people usually count what is in addition to being at rest/sedentary. But the total reported by this calculator includes the basal rate. That's why it's so high.
i don't know where you pulled the data about 10k steps, but even if it was accurate, it would depend a great deal on how much weight. At my weight, running (!) for 30 minutes burns a mere 200 calories.