Dear friend, I think it will be very similar to Sweatcoins, maybe you should add something else to make it different. The "Walky" name is good, I like it.
It could include other activities, for example food, that the user says where he eats, what movie he sees, what TV program.
good luck !!!
I think the challenge is indeed to be different enough than Sweatcoins.
Sending 2 shares.