Your take is fair. Walkfit helps new walkers start, but bugs, syncing, and auto renew hurt value. Treat it as a 30 to 60 day nudge, then cancel if steps hold.
Simpler alternative: use a wall calendar and a cheap pedometer. Goal, 20 minutes daily or 6k steps. Each day write start time, steps, mood score. Put $25 with a friend as a stake. Miss 3 days in a week, they keep it. Share a photo of the calender every Sunday. This hits commitment, visibility, and feedback without a sub. It works, even for messy weeks.