He's a fan favorite that every player has used at least once, and every card collector probably has in their deck
In the Pokmon Evolving Skies TCG expansion, a similar Rayquaza card reached upwards of $550 in value
There are 138 Green and Black Insects, which gives you enough for a Commander deck but not that many options
And the planeswalker Liliana of the Dark Realms harnesses the power of Swamps for a variety of delightfully evil purposes.
Its sky-high price demonstrates the high value collectors place on CGC Cards' Pristine 10 grade." The "Pristine 10 grade" is as good as you get but, even then, the $3 million price tag is remarkable
If this thing was a named legendary creature - even if it was a new version of that weird little rat Loot - it might feel like a mythic rare, purely on the basis that "cute little guys" is an established archetype for extremely rare and powerful creatures