You will hear differently from the Blueprints-only crowd here but I personally feel that Blueprints with a moderate level of complexity quickly become an unmaintainable mess of nodes and crossed wires. C++ code will scale much better in terms of readability in my opinion.
Additionally, Blueprints can’t be properly diffed by version control systems since it’s binary data. There is a diffing tool in the editor but it doesn’t compare to the textual diffing offered by git or Perforce.
That is not to say you should avoid them. Blueprints shine when you use them to script high level gameplay interactions supported by a solid foundation in code.