Most general users of apps on phones wouldn't give an absolute crap if you "fixed a buffer overrun in the X function", because that means nothing to them. If they read that you've made performance improvements, then great they can continue to play Candy Crush but not have it crash so often. They won't CARE that you "optimised the use of the strcopy function" or some crap like that.
Remember the app stores are targeted towards consumer users of phones, not tech people that live on Hacker News websites.
Most general users of apps on phones wouldn't give an absolute crap if you "fixed a buffer overrun in the X function", because that means nothing to them. If they read that you've made performance improvements, then great they can continue to play Candy Crush but not have it crash so often. They won't CARE that you "optimised the use of the strcopy function" or some crap like that.
Remember the app stores are targeted towards consumer users of phones, not tech people that live on Hacker News websites.