Should I lock to portrait my iOS app?

1. Why do people use portrait orientation lock?
2. What does portrait lock do on iPhone?

Why do people use portrait orientation lock?

Turning on portrait orientation locks the screen so that no matter which way your iPhone is turned, the screen will stay in place. Instead of your iPhone screen flipping between portrait and landscape view, you can use portrait orientation lock.

What does portrait lock do on iPhone?

You can lock the screen orientation so that it doesn't change when you rotate iPhone. appears in the status bar (on supported models).