If you could reliably cast this off of a Mountain, a Forest, and a Swamp, that would be great, but that's not an option
This is exactly why Sneak Attack is such a popular (and intimidating) card in Commander decks
As token makers go, things like Decree of Justice and White Sun's Zenith (two other cards many of you mentioned) will ring as stronger, but none will draw as many laughs as Flock of Rabid Sheep
Parasitic Grasp Black-based removal is so good in Standard that any new member of the club must endure high scrutiny
Mill seems to be getting hooked up with more ways to close a game, doesnt it
Ultimately, this is a placeholder solution so that more time can be spent on fingerprinting and identifying headless browsers (EG: via how they do font rendering) so that the challenge proof of work page doesn't need to be presented to users that are much more likely to be legitimate