In this format more than any other, reusable removal spells were at a premium, such as Skull Catapult and Stormbind
You want your Cascade triggers to hit ramp early, value in the midgame, and more threats or setup pieces once you are ready to close
It is also why black is the most common colour alongside blue in legacy and vintage where you need to have some interaction with spells and their potential to be cast so as to not get run over by broken things
Synergy thats actually worth it
If a card with storm creates copies, each copy will trigger the magecraft ability, allowing for a ton of triggers off of one spell
That means that Blightbelly Rat gives two poison counters, and Ichor Rats and Septic Rats generate three poison each when they connect with an opponent