Advantages of space colonies
Let's talk about some advantages of space colonies.
The planet earth might not be here forever. Humans will either destroy it, or it could get hit by a giant asteroid. The biggest advantage I see here is survival. Not only would people in space colonies survive and prevent the human race from becoming extinct, they would also be able to go to earth and help others after a huge disaster. The people in the space colonies could save many lives.
Another, maybe lesser important advantage, is entertainment. With low gravity, you could become pretty entertained. I've seen the astronauts in the ISS play around, and they admit to the fact that they enjoy it. We'd have a whole new level of entertainment, nothing like we've experienced here on earth.
Peace. Is it possible? We have experienced war since the beginning of time. Countries have invaded other countries. Greed, religion, money, power, those are all reasons why wars have been fought, and more. I just can't imagine a war between space colonies. How would they even invade? They'd all die.
Environmental advantages. If pollution on earth becomes worse, we'll all suffer because we don't live in a bubble, but if a space colony gets pollutes, not everyone suffers because the space colonies would all be separate entities and they would not share the same air.
Prevention of over population could end up being a serious benefit of space colonization. The human race is multiplying faster than it ever has before. The earth is a huge place, think of all the areas where you won't see a human, but that will change a few centuries down the road, or maybe even sooner.
Sending large amounts of people to space colonies would also keep pollution on earth down. Keep in mind that the earth's population is expanding rapidly. With it comes pollution, damage of the ecosystem, and more.
Space colonization could, and probably would, also bring new scientific possibilities. It would also mean more resources.
On the list of benefits, I'd also have to add Happiness. Colonists would be people who are passionate about space colonization (Otherwise you wouldn't leave everything behind here on earth). They would be doing something they are passionate about, something they like to do. Done with that boring 9 to 5 job where the boss is watching your every move.
Less stress. While I think there would be lots of work to be done in a space colony, there would be less stress all together. Much of the stress you have on earth, you would not have in a space colony. Things like your car breaking down, too much to do and not enough time to do it, etc... none of that would be an issue in a space colony.