Why is this the answer?

The answer is compass because this clever riddle describes a super useful and simple tool that helps people find their way. Let's look at the first part of the riddle: "I am so simple that I can only point." If you have ever seen a compass, you know it is a very simple thing. It usually has a spinning needle inside a round case. That needle is its only job! It does not sing, talk, or walk; it just points. This makes it a very simple tool, just like the riddle says. What makes that needle point is a wonderful natural force called magnetism. The Earth itself is like a giant magnet, and it has an invisible force field all around it. The small needle inside the compass is also magnetized, so the Earth's magnetic force pulls on it, making it swing around until it lines up and points to the Earth's North Pole. It's a tiny piece of science right in your hand! Now for the second part: "Yet I guide men all over the world." How can a simple pointer guide people everywhere? Well, since the needle always points north, you can use that as your starting point to figure out every other direction, like south, east, and west. Knowing the directions is called orientation, and it is the key to traveling correctly. Think about people who explore new lands, sailors who cross huge oceans, or pilots who fly large airplanes. They all rely on the compass to know exactly where they are going and to make sure they travel safely. The compass is an invention that has been helping people explore and travel all around the globe for hundreds of years. Without it, finding your way would be much harder! Even today, when we have super advanced technology like GPS, the trusty old compass is still a reliable tool because it doesn't need batteries or electricity, proving that even a simple thing can be extremely powerful in guiding the world. It perfectly fits the riddle by being simple and yet guiding millions of travelers.