A good pocket flashlight is a very useful thing. A flashlight can help in a variety of situations and save the day in the event of an emergency. Carrying a flashlight with you means you're never far from it, and you can always illuminate something dark.
A good pocket flashlight is usually part of someone's EDC (every day carry): something they carry with them wherever you go. For many people, a flashlight may be more useful than a weapon, pen or multi-tool. Pocket torches can be used indoors, whether in dark spaces such as under the sofa, or at night, such as when going to the bathroom without waking up the family.
Many bright pocket torches are also suitable for outdoor use. For example, walking to your car at night or finding a path. They are also a great safety tool for securing an area and signaling others.