Everything from artwork to build quality can differ between regions, which can make certain versions more desirable than others
Dire Fleet Hoarder put in a lot of work in Limited formats, and I expect Undercity Dire Rat will do much of the same
Like its kin, the Igniter has a triggered ability that prompts you to pay mana to use it
The deck has decent staple reprints, notably Academy Ruins, Panharmonicon, Conjurer's Closet, Arcane Denial, and Lightning Greaves
This will still often paired with secondary combo wincons, most often storm combo or other options which overlap significantly with the prowess card pool
Furthermore, simply telling players to ignore that until your next turn is much, much more intuitive than explaining the vagaries of flickering, and there are very few situations where phasing effects need any more thought than that