It gives a fantastic buff to your artifact creatures , with melee, haste, and trample, but part of the mana cost is for the ability to turn your regular artifacts into creatures
This obviously includes sorceries, but most permanents can only be cast/played at sorcery speed
Simic Signet
But as an instantit's still kind of meh
While both Hallar and Verazol play very differently, with Hallar being an explosive Burn deck and Verazol being a durdly value engine, both have a ton of overlap in terms of the cards they're using
With three mana, you can play plenty of great commanders, cast tons of mana rocks, and have access to all sorts of other ramp spells