So it should have been carved into a giant lightning bolt since that's what ended up destroying it then? /s

Humans are the ones capable of understanding artistic expression. It's pretty, and sends a message to humans which helps them empathise with the natural world. Squirrels aren't going to care if it looks like a hand, or a tree. I don't understand the criticism. It's a cool art. There are lots of trees which rot normally, but this gesture shows humans that they are part of the world with apparently no lasting environmental consequences.