Its monster effect is the part of the card that other Dragon-type decks make use of, as it prevents both players from special summoning monsters from the extra deck
Toski doesn't encourage your opponents to attack each other like Bill Nighy here does, true, but Edric is most often used in "Flying Creature" builds that use cheap cards like Flying Men, Scryb Sprites, and Pteramander to draw a bunch of cards
Giving three +1/+1 counters is very situational, and outside of Simic +1/+1 counters deck, its not a good effect
According to data from Scryfall, 118 cards have the rat creature subtype
This cleared the way for attackers, and took care of bothersome utility creatures
Hammond gazing at a mosquito captured in amber