Around the home
If you have a multi-tool in your top drawer you'll be surprised how often you'll use it. So many little jobs around the house don't require trekking to your garage for a specialised tool, instead you just need your multi-tool! If you have a multi-screwdriver on hand, the multiple bits means you are almost guaranteed to have the right bit for whatever you are fastening or unfastening.
In the outdoors
Most of the time going into the outdoors means you are restricted in what you can take with you. That's when a multi-tool comes into its own. In one lightweight multi-tool you have all the tools that you need for whatever situation you need it for, whether it is sawing a branch from a tree, hammering in a tent peg or simply removing something hot from the campfire. Pocket knives are also extremely handy in many different situations in the outdoors.
In emergencies
You never know when you might find yourself in an emergency situation and if you do a multi-tool can sometimes mean the difference between life or death. Having a multi-tool in your car or in your emergency kit is a precautionary measure that means you are prepared for anything that may happen.