I'm playing the core set of Star Realms and I find myself picking up the Stealth Needle and Mech World whenever I can afford them. Because of their abilities to mimic other factions, I really don't care what faction(s) I'm focused on. The Stealth Needle can only mimic one other faction in a turn, but it also retains the ability to ally with Machine Cult. So it's possible to imagine an alternate design where Stealth Needle belongs to another faction and it makes a difference in the game.
But Mech World is a whole nother story. Since it counts as an ally for all other factions, the Machine Cult color and emblem are superfluous. As far as I can tell, it would work just as well as an Unaligned card like Explorer, Scout and Viper. Obviously there's a lore component here. Machine Cult is the only faction devious enough to invent this type of base. But I'm thinking in terms of the game's mechanics, so to speak.
So for the core set, does the Mech World faction matter in terms of gameplay?
Bonus: Are there rules in any of the expansions that make the faction of this card matter?