Well, integration is one aspect, and there are low-code tools like node-red etc. for those use-cases. One category of low-code tools is workflow automation tool

Well, integration is one aspect, and there are low-code tools like node-red etc. for those use-cases. One category of low-code tools is workflow automation tools, which maybe you are describing mostly. For me, I am interested in writing the business logic using functions. And what comes to the actual backend the data flow is the "normal" one: User <---> API <---> Business logic <---> Database