I think Webpack has the monolith advantage here. It allows you to add things that would otherwise be immensely complex with ease because it can do a lot. You can have it handle bundle splitting and async loading of modules, image optimising and hashing, CSS/SASS/... processing, ...

Since we started using Webpack where I work we've stopped using all other build tools. There's very little Webpack can't do, and the main advantage is that there's no need to hook things up to eachother since it's all part of the same system.