If you really want to "quickly prototype" a game with Phaser 3, the easiest way for me has been to just include Phaser from a CDN, download the Phaser TypeScript definitions, and then just start an HTTP server. Adding a tsconfig.json is just one extra, optional step.
If you're just prototyping a game concept, you probably don't need a module bundler/Webpack at the start of your project; either you have to download a starter kit, or spend time working out your build configuration. I personally just think it makes more sense to figure out the build later on, when you intend to release an optimized bundle.
I have similar complaints about Polymer's PWA starter kit (which comes with an entire Redux setup and more). In general, I just think starter kits should be the absolute bare minimum, rather than being opinionated.