Most sites will serve with brotli compression to browsers which support it (i.e. all modern ones). Logging just the uncompressed size is somewhat disingenuous; pika.dev and friends show compressed sizes by default as it is true what most users will actually download.

Example output:

$ vite build
vite v0.13.0
\ Building for production...
[write] dist\assets\index.js 8.41kb, brotli: 3.15kb
[write] dist\assets\style.css 0.00kb, brotli: 0.00kb
[write] dist\index.html 0.22kb, brotli: 0.10kb
Build completed in 1.10s.

On the very small app I tested this on, calculating brotli sizes added ~3% to the build time.