The flying tokens that Rootha creates can both help prepare this card and are going to be good target to copy as well, not to mention anything else you might create with other spells or abilities
I run Draining Whelk in a bunch of my Commander decks for y'all, as one example, as well as Mystic Snake, Voracious Greatshark, and Overcharged Amalgam
Even better, with Eloren Wilds chaos ability, you can start shutting down your opponents by preventing them from casting spells until a player planeswalks away from Eloren Wilds
Milling yourself is not a supported theme in Adventures in the Forgotten Realms , so I would save this for Sealed
I think this does get relegated to higher power pods where doing this sort of thing has more bearing than brackets 1-3, but it's likely going to see a lot of play in a similar scenario to Swan Song