Yes there are good reasons for going to Mars. Greatest among them is to safeguard the species from any catestrophic impacts on Earth they would extinguish us.
No potential impact to Earth would render it less hospitable to life than Mars is. For speicies survival a set of fortified underground bunkers/mini-cities would be far more practical -- and unlike Mars, we do have the tech to do that.
The suggestion that we currently have the technology to colonize Mars is, in brief, ridiculous. No human has been move than 500 miles from Earth's surface in over four decades, and the farthest we've ever sent a human is under 250,000 miles; at its closest, Mars is 38,000,000 miles away. We do not know how to safely get a human being that distance through interplanetary space, and the first few people we try to send are quite likely to die.
That investment of blood and treasure might be worthwhile if there was something useful for humans to do when they got there, but there isn't. We'll get better scientific results by building and sending better robots.
There is no practical reason to send humans to Mars in the near-term -- say, next five centuries. Especially not when all of our resources are needed over the next century or so to put human civilization on a sustainable footing. We can probably do some useful stuff with humans in Earth orbit and maybe on Luna, but deep space is for robots.
The only justification to put humans on Mars is some vague hand-waving about "inspiration" -- i.e., it's a huge performance art project. Maybe someday humanity can afford that. But not now.