What Is a Game Server and Why Rent One?
A game server is the computer players connect to in order to share the same world, and it enforces the rules of the game. It calculates every player's position, inventory, every structure and every hit, so the server's speed directly determines how smooth the game feels.
Hosting a server on your own PC can be enough for a short session with friends, but when the PC shuts down, so does the world. Home connections have limited upload speed, port forwarding needs router settings, and your home IP address is completely exposed to DDoS attacks.
A hosted game server stays online 24/7, serves dozens of players at once over a data centre connection and absorbs attacks for you. You only have to focus on your community and your game.