The math on this is absolutely hilarious.
For 3,650 coins, you get a $50 gift card. If you're getting one coin per 1,000 steps or so, with the average men's stride being about 2.5 feet, you're in the neighborhood of one coin per half-mile. So that makes about 1825 miles you have to travel to earn a *$50 gift card*.
But before you take off on your walk from Portland, Maine to Miami, Florida to grab your $50 gift card, you can only earn 570 coins a month. You also can't earn more than 20 coins a day, so in a 30 day month, you have to walk at least 10 miles every single day to get to 570 a month (600 minus the 30 you have to give back to them as "payment").
So after your 1825-mile walk, which you've spread out evenly over ten-mile strolls over seven months, you finally get that $50 Nike gift card, which will score you half of a pair of shoes! Of course, since the typical recommendation for when to replace shoes is 500 miles, you're also on your fourth pair of shoes.