Hot? yes, but apparently cooler than England right now as long as you're a meter below ground in a ring around the poles (how's a constant 21c/70f sound)
this guy's website is so weird but I love the novelty of the idea and he portrays a plausible scenario for it being ultimately more habitable than Mars
yeah, the infrastructure that interplanetary colonisation requires would also be enough to detect + deflect large asteroids, and would also be vulnerable to the far more common big solar flare wiping out all precision electronics, both in space and in inevitably tech-dependant colonies