Even if you couldnt activate Scavenge in response to itself, it would still be possible to return the card with Scavenge from your graveyard to your hand in response to the activation, allowing you to cast the card later or discard it to Scavenge again later
You kill the token and it crews up a blocker meaning two removal spells are needed to get passed it
Dont get me wrong, its a solid concept but during testing, I found two situations to be very prominent
Why not put that effort into getting better
The value difference between shadowless and shadow bordered cards rises even higher in the case of "first edition" stamped cards
However, every Pokemon is loved by someone, and if you didn't count yourself among those who love Mankey before reading this, then maybe these cards will convert you into a Mankey fanatic