Hi,
If finally you need to deploy your bot, you need to register your bot to Azure anyway. If you only use your bot without deploying, you don't need to do that.
For your scenario, it's much better if you do the registration before. You can moderate everything by Azure portal and it will be much more convenient for further development.
More samples and information please see: https://github.com/Microsoft/BotBuilder-Samples/blob/main/README.md
Regards,
Yutong