The very good thing about module bundlers versus transpilers and task runners is that changing a single file doesn't result in a complete rebuild of the project; since the bundler maintains a model of the dependencies between files, it only needs to recompile the files that matter.
The downside is that now you have a whole other ecosystem of tool wrappers that tends to lag behind the tools themselves. They also tend to be JS specific, so if you have any other assets, you'll still need a regular task runner.
