The advantage of frameworks isn't that they make it easier to write the actual agent, it's tooling + observability + ... Even Langchain, for all the (deserved) criticism it gets made this very clear very early: It might be easy/easier to write your own chatbot from the ground up, but what happens if you have to add observability/tracing? Being able to just add one environment variable and instantly have a UI where i can nicely go through all of my traces with basically 0 additional effort is something a hand rolled solution just can't really compete with
This only becomes relevant if your execution graph is complex/big enough. Otherwise, all it takes is less than 30 minutes to add telemetry to all needed points. Doing manually also gives you better control on what you really want to track (to save costs).