I&#x27;d propose the following distinction, especially for React users:<p>If your components will only ever be used by you or a small, internal team of programmers, then inline styles can work.<p>If, however, your components are meant to be re-usable, public and accessible then CSS is still a <i>must.</i><p>To pick on one project react-datagrid is a super useful, public component for displaying data, but they use inline styles, which makes integrating the component into <i>any other design</i> a nightmare. You have to fork their codebase to update a style because you can&#x27;t over-ride it and there&#x27;s no way they&#x27;d pull in a PR for your preferred style.