I tried LangChain a while ago for a RAG project. I liked how I could just plug into different vector stores to try them out. But I didn't understand the need

I tried LangChain a while ago for a RAG project. I liked how I could just plug into different vector stores to try them out. But I didn't understand the need for the abstractions around the API calls. It's not that hard to just call these APIs directly and its not that hard to create whatever prompt you'd like.