I think the important part is responsiveness. I once made an app with an export feature. It was pretty slow (I benchmarked it against other tools and my tool w

I think the important part is responsiveness. I once made an app with an export feature. It was pretty slow (I benchmarked it against other tools and my tool was an order of magnitude slower) But it was extremely responsive. The status bar updated frequently and was accurate, and a cancel button responded immediately. People in reviews wrote that my app has great performance! Nobody complained that an export would take a minute! I did not expect that. But then I realized that perception of speed / responsiveness is more important than actual speed. My app reacted instantly to user input, and never lagged, even while processing an export. I even wasted a lot of CPU cycles updating the UI to show status. But the result was an app that felt fast, and people really liked it.