The longer you can wait to tell your opponent something, the more opportunity there is for them to make a play they wouldn't have made if you had played that card earlier
Draft and sealed force you to work with whatever colors you open, teaching flexibility
The other option is to go full land ramp which can be vulnerable to Winter Orb, Armageddon and effects like that
By lowering the cost of each of these tutors by , having them only focus on a specific card type, and having them place the card on top of your library instead of into your hand, these one-mana instants were meant to be more balanced versions of the original tutor
When you consider all the problems that an initiative like this introduces, its hard not to agree with them
Adventures can spice up many archetypes in MTG, but Beluna can consolidate them into a functioning, powerful deck of their own