The certificate is used for nothing more other than checking whether the launcher is "signed". The whole scheme is full of security holes, the certificate check mostly seems like it was a programming exercise for the author.

There is no need for the certificate installation with regards to any emulation functioning. Also, worth noting that this is an ongoing issue: this reboot of the game still has a decent daily player count and the CA installation concern has not been addressed, the launcher still does this.

(It's also not a server emulator, it's just a launcher for the game client, used by players of the game.)