Whenever one or more creature cards leave your graveyard, all your opponents lose 1 life and you gain 1, which can translate into a win with the right setup
Carrion Feeder being a Zombie can also come into play when looking to bring back Gravecrawlers in some sort of Bridge from Below / Vengevine deck
Beast provides plenty past his entrance to the table, too, with four strength and four willpower to help in challenges, and two precious lore points when he quests
As far as the free-to-play element goes, Pokmon TCGOs progression is paced a little slowly for those who opt out of microtransactions (and, in this case, buying packs of cards IRL that contain redeemable codes)
Compared to clumsy effects such as requiring only Insects to be present in the graveyard or requiring a large number of Insects, the conditions are poor, making it difficult to use as a general-purpose Insect type card