First of all, as a host, you need to have the ability to recite lines, pay attention to methods and be able to recite lines quickly and accurately.
Secondly, as a host, you can't make mistakes when you are familiar with your lines, which will make the program look better.
Finally, memorizing lines can help you control the scene effect well and improve your ability to deal with emergencies.
I hope my answer can help you and look forward to your adoption.