Multiplayer game without multiplayer object

If I am running a game on a server (which is also the host) and the players only play the game while on-line and connected to the server, do I need to use the multiplayer object? If the server is constantly running then the players could have separate Sprites and using instance variables/UID accessible only accessible with players using their UserID and password.

Does this make sense? My goal is to keep it as simple, secure, as possible. The game isn't particularly heavy when its comes to computing power.

Thanks for any feedback.

You need the multiplayer object for the host and peers to connect and communicate with each other, unless you are using a third party networking api with something like Photon or Firebase ect.