I use photography editing apps all the time like Lightroom and Photoshop, but I do also use the photo app on the iPhone and iPad to edit photos. It has certainly come a long way and you can do some much in adjusting exposure, contrast, highlights, shadows, colour and so much more.
One that caught my eye was brilliance, I had not seen this before in the other editing apps and wanted to know more about it.
It kind of does the opposite to contrast in that it make the highlights less bright and the shadows brighter. I always like adding contrast but I do like this for the right photo, there have been times I have adjusted the highlights and shadows to get the same effect, so now they have made it more convenient. In fact I have added both to sometimes get a particular effect.
Why not give it a go yourself.