Because he wants it clear of the snow. That is apparent by the second slide. In its mind, the snow is not as stable a surface as the roof, even though it's slipping on the roof.
Standing on it to keep it still while he picks away at it, and sliding down by accident. Interesting, but he doesn't really look like he's enjoying it.
binc, I think you're right about that.
I'd rather spend the $5 on myself.
The English penny is called a Cartwheel penny, since they are "as large as cartwheels". They also made a somewhat larger twopenny. I have both kinds.