I won't recommend turning on the feature. You must remember that a flashlight consumes lots of battery power. So, if you're trying to turn it on when your phone battery is low, it might not work.  Moreover, a lot of phones have a setting to automatically turn off the flashlight as soon as the phone battery goes below a certain level, which is fixed in different phones. This level varies from brand to brand. It ranges from 20% to 5%. If your phone battery is in any of the above ranges, it will automatically turn off its flashlight.