Yes, the evaporating cools down the room, though I can't say I ever noticed it. In terms of energy efficiency compared to a dryer, it's much better in summer, and not much better in winter, though you get a humidifier as a freeby.
Yes, it's a chore, a full load takes about ten minutes to hang, and it's real boring work.
The dryer wears down clothing very quickly with friction.
Cannot imagine additional longevity would be worth all the work of manually doing it.
I doubt Uniqlo clothes last five years while tumble dried. I hand dry the few t-shirts I own from them and after three years I wouldn’t wear them as anything else than bed wear.