I don't disagree with the main point here, but the dev-dependencies won't be installed or run on your machine unless you're building Tailwind or Panda itself. They're not necessary for processing the CSS.
As far as I can tell installing a package will also pull down all of its dev dependencies. This unfortunately leads to many typescript related annoyances such as jest typescript global types being pulled in despite not needing them.
How much do they care about simplicity, bloat, efficiency, security? The number of dependencies is a signal. Maybe not an important one, though.