The doto macro was a relief back in the days when Java APIs insisted on being designed around stateful setters and getters rather than the builder pattern, it allowed you to operate on such unfortunately designed objects in single logical blocks and simulating it all being an expression.
Proxy allowed you to instantiate anonymous inner classes implementing only the methods of an interface that you needed, the rest you could omit; in Java you have to put them all, empty, which necessitated that you use an IDE to generate them, and back then IDEs were not as nice as today.
Those two alone made interacting with contemporary Java libraries so much easier.
It also was convenient to go from Java collections to Clojure collections and vice versa.
The doto macro was a relief back in the days when Java APIs insisted on being designed around stateful setters and getters rather than the builder pattern, it allowed you to operate on such unfortunately designed objects in single logical blocks and simulating it all being an expression.
Proxy allowed you to instantiate anonymous inner classes implementing only the methods of an interface that you needed, the rest you could omit; in Java you have to put them all, empty, which necessitated that you use an IDE to generate them, and back then IDEs were not as nice as today.
Those two alone made interacting with contemporary Java libraries so much easier.
It also was convenient to go from Java collections to Clojure collections and vice versa.