Its the new thing in teaching kids to ride bikes. They start with a push bike, and supposedly will never need training wheels. Since they don´t have to worry about pedalling, its easier to work on their balance, and on steering.
Basically whenever we leave the house for a walk, my 2 and half year old is riding his (though its not quite as nice as OPs). He can´t/wont keep with us walking, but put him on the bike and its hard to keep up with him. He can do a few kms that way too.