Drag. Friction. Weight distribution and load. These are things you need to consider when you begin to think about how tires work.
Yes, those four bits of rubber are your only connection to the ground and they keep your car moving in the direction you desire. Most of us think that a wider tire is better, and if it's more grip you seek then you're probably right. This is why.
Jason from Engineering Explained is ready to break it all down. Basically, you want an evenly spread load across your tires. If you make your tires wider, it becomes easier to achieve this. A larger contact patch on the ground will allow you to accelerate more quickly, stop in a shorter distance, and handle higher cornering speeds.
Now, that's if you compare a vehicle with one set of tires to the same vehicle wearing a different set. You can't have tires that are too large for the vehicle to handle, and you should be comparing the same type of tire to another. A wider winter tire typically won't offer as much performance as a slightly more narrow high-performance tire.
There's a lot of science to be explained on this one, so we'll stop talking and let Jason take over. Hit play above to gain some important knowledge.