If you want players to connect to your server using a custom domain (e.g., play.yourdomain.com) without typing a port, you will need a Dedicated IP.
Without a dedicated IP, your server may share the same IP address with other servers. In that case, players usually need to connect using a port number (for example: play.yourdomain.com:1234).
With a Dedicated IP, players can simply connect using your domain name without adding a port.
A dedicated IP is optional, but it provides a cleaner and easier connection address for players.
If you need help with this, please submit a ticket.