Welcome to Microsoft Q&A! Thanks for posting the question.
It would depend on your use case/scenario whether you can use the azure service bus instead of SQL service broker.
SQL Server Service Broker is the perfect choice for the cases where you need messages to be processed in a sequence inside SQL Server itself. Of course, it can be used otherwise too.
Whereas the service bus is a fully managed enterprise message broker with message queues and publish-subscribe topics. Service Bus is used to decouple applications. I will suggest you to review this to learn more about the use of service bus and see if it fits your business scenario.