Thats because the regular tokens strategy has basically been completely outclassed by Hare Apparent decks at this point, so the only reason youd care to run Slime Against Humanity for tokens is if you care about Oozes in particular.
The low cost makes it an efficient way to put a stop to tons of strategies that rely on shenanigans to generate a ton of value
And out of all the ACE SPEC cards, this is the one you want as it sort of breaks the game
Thorn of the Black Rose: [Monarch Card] Except for the monarch bit, it's just another common creature to get that limited creature count up
Note that even though the last week of previews was cut short by the full set spoiler, the last Friday was still officially part of the last preview week, so it was still considered two (or in the case of Scars, three) weeks of official previews
Reprints in the deck include ramp cards like Cultivate and Rampant Growth, Tribal cards like Icon of Ancestry, and counters-focused stuff like Hardened Scales and Bred for the Hunt