“To help people build more software, faster and easier.”
Faster and easier, after you rewrite every responsive class from .d-md-none to .md:d-none. That is Tailwind syntax with a Bootstrap logo on it. The plugins go ESM-only, the window.bootstrap global is gone, and v5 has no end-of-life date yet. Every CDN-and-a-script-tag site just got a migration project.