So its a bit more obvious when a Trainer card is good for its drawing or searching abilities
(EDHREC Rank: #618) Much like Patron of the Moon, Multani benefits from a lot of cards that have been printed in recent years that care about the number of lands you play, so if green is more your speed, you should give this a consideration
Most decks in the game will not go above 40 cards to help with consistency, but some play styles, like the Lightsworn archetype or decks used That Grass Looks Greener before it was banned, can benefit from more cards
The main issue is going to be the back
If there is no wager on the current betting round, a player may bet
The key is to only make these kinds of picks in spots where theres a low opportunity cost