Yes. You just have to understand that DR and Backburner are different concepts of network/distributed rendering.
In case of animation, Backburner is more a kind of "batch rendering manager" with the benefit that scenes+assets are loaded only once per node (they just switch timeline when changing to another frame instead of reloading the whole thing. Here is potential for improving Corona DR btw.). So Backburner should be your first (no charge) choice when it comes to animation frames.
In case of stills, I would not recommend to use Backburner as distributed (! meaning processing one frame on multiple nodes) render solution because you would have to use its strip rendering system, which may cause issues using any postproduction features of Corona. So yes, Corona DR is the choice for rendering distributed stills.
Of course it is fine to submit your 4k stills to Backburner (without strips) for overnight rendering though, because it then also just does a one frame on one node processing. And you could even mix both, Corona DR and Backburner by sumbitting a job to one node in Backburner while having Corona DR slaves assigned in the scene.
Good Luck