The auctioneer has the right to decline, reject, and or refuse any bid, from any venue
Also, tokens are great permanents to leave the battlefield
With access to counterspells, redirects and cheap reanimator, they need dealing with to stop their inevitable domination
Still, the adventure sorcery aspect of this card also brings a ton of value, especially given that mill is slowly creeping back into the Standard and Commander metas
I suppose theres an off-chance that Mono-Green Aggro wants this, but that would involve Mono-Green Aggro becoming an actual deck again first
Shalai and Hallar takes the aggression further by damaging your opponents when you add counters