The sets new mechanic allows you to make one creature into a powerhouse that can make everyone lose extra life, stop them being blocked and even turn them into a legendary creature
Finally, there's probably a small group of players who want the cards for unique reasons, like building an Un-set cube (which becomes a lot more realistic with three Un-sets rather than two) or even Un-set collectors, which I'm sure exist in some number, although this last group has to be pretty tiny
As for red-white Equipment aggro, plenty of cards encourage a low-t0-the-ground, proactive deck made up of white and red cards with plenty of Equipment and combat auras to augment its warriors
1 Tomb of the Spirit Dragon
Most of them are legendary lands with a trigger
Winter descended, and now she must work with trusted allies to set things right