A gaming mouse has extra buttons, better sensitivity and software that allows for macros. It also has a more ergonomic design and may have RGB lights. These features can add up to a higher price tag. But is it worth it?
It depends on what kind of games you play and how competitive you are. If you are a casual gamer you don't need a high-end gaming mouse. However, if you are into MMO's and RTS's with lots of clickable buttons a gaming mouse could be a good investment. Gaming mice can also help with aiming in shooters since the programmable buttons allow you to assign a different DPI for precision sniper aiming or twitchy on-the-ground firefights.
The main advantage a gaming mouse has over a traditional office mouse is its higher polling rate. This means that the mouse is sending its position to your computer a lot more often, usually up to 8000Hz. This translates into smoother, more fluid gameplay.
Gaming mice also have a lower amount of latency, the time it takes for your button presses to show up on-screen. This is usually a big deal when it comes to gaming, especially in fast-paced shooters where every millisecond counts. Lastly, gaming mice often have adjustable weight so you can add or remove a few grams to change how heavy the mouse feels. This isn't a feature that all mice have, but it can make a huge difference in comfort.