This is a very interesting contest and is perfectly suited to my recent Dream Game post :) I'll have to stick with my initial choice.
My superpower would be teleportation. Being able to go anywhere in the world in the blink of an eye, without bothering about travel issues or any other problems - well, apart from luggage, as it would require plenty of back and forth. The uses are endless and it could bring a lot of good to the world
I would choose teleportation right now, because I've considered some of the uses for it and they would really do some good. For example, I could appear from thin air in hostage situations to take the kidnappers out of the place and into a jail cell, or step into a raging fire and take the victims to a safe place. There are so many applications that it would really benefit a lot of people...
... But every superpower has a few downsides. One of them would be landing a few inches from the desired place and screwing up any timed event that needed extreme precision. Or becoming so fat and unhealthy because I completely forgot to exercise as I prefer to teleport from place to place :)
The two posts did tie in quite nicely!
Teleportation would be a great power to have, although as you mention here (and I alluded to in a different comment), it would be tricky to know how and where you would reappear. Accidentally materialising into a newly moved piece of furniture could prove painful... Unless you happen to have a noclip setting...
Or materialising right on top of Lego bricks... That would be extremely painful :D
The winners and the new question (I've told you how to do this before...) is here:
https://steemit.com/newbiegames/@bengy/steemitbasicincomegiveawayivetoldyouhowtodothisbefore-pb6n4om11j