Its something that theyve been doing a fair amount of lately to gate the power of cards, and Im of the mind that they should continue
Avoiding permanents is probably the easiest way to meet the restriction since playing a deck with a bunch of creatures while also ensuring each has an activated ability seems difficult
In Magic: The Gathering, sometimes you'll have a handful of rubbish, your best cards disobediently hiding somewhere within your deck
While there are no precon decks for them, savvy players can build their own based on the characters' abilities
Alternatively, cards with incredibly strong internal synergy, like Arcades, the Strategist or Tom Bombadil, are amazing in bracket three
Intent is the most important part of the bracket system