Why? With such a well-known framework like Spring, you will get the benefit of any Spring-developer knowing instantly the conventions (which is not true with your in-house conventions where I will have to hunt down where does this class come from, oh this ugly abstraction which is buggy as well), less code is less opportunity to introduce bugs, less thing to maintain. Annotations are basically just a declarative DSL for a significant chunk of your code base.

I really don’t see any cons, other than a slight learning curve (and yeah sure, “developers” that just bash keys will have trouble with understanding what does an annotation do and blindly copy-pasting them can be dangerous but they will also fk-up regular code as well..)