The idea here is that you play this in the toughness matters deck, and I think youll play this reasonably often there, but you wont really be playing it anywhere else
Brain Crusher is a LVL7 monster with 2400ATK/1500DEF, and it has a great effect where during the End Phase, if this monster destroyed one of your opponents monsters, then you can Special Summon that monster to your side of the field
Once you unlock and play through more gates, you obtain completion bonuses such as Gems, structure decks for an archetype, cards, and elemental orbs
All this on top of being a 3/3 with menace for three mana makes Byway Barterer great in Limited and Constructed environments, but maybe a tad bit slow in Commander
It can evolve on a lower level Digimon for its digivolution cost or can be played outright for its play cost with abilities that trigger off of those choices