While Shadcn, Daisy UI, and Tailwind CSS have indeed gained significant traction in the web development community due to their ability to streamline and augment the design process, many developers still find value in using vanilla CSS. Here are some reasons why:
Foundation Knowledge: Understanding the core principles of CSS is crucial. It ensures that developers can effectively use and customize frameworks. Without a strong grasp of vanilla CSS, one might struggle to debug or extend styling capabilities beyond what frameworks offer.
Fine-Tuned Control: Frameworks provide a set of predefined styles that can accelerate development but sometimes at the cost of control. Vanilla CSS allows for more precise adjustments that cater to unique design needs which might not be possible with a framework’s default options.
Performance Considerations: A well-written vanilla CSS can reduce the unnecessary load. Frameworks often include styles for functionalities that may not be used in a project, leading to bloat. By crafting styles from scratch, developers ensure that only the necessary CSS is included.
Learning and Experimentation: Engaging with vanilla CSS helps in experimenting and understanding CSS features and new functionalities. Keeping up with and getting hands-on experience with the latest CSS specifications can be beneficial for developers to enhance their skill set.
Legacy and Simplicity: Some projects, especially smaller or legacy projects, may not warrant comprehensive framework features. In such cases, vanilla CSS can be more straightforward and less overbearing, making maintenance simpler.

Ultimately, whether a developer uses frameworks or vanilla CSS largely depends on the project requirements, team’s skillset, and personal preference. Many developers choose a balanced approach: leverage the convenience of frameworks where applicable while relying on vanilla CSS for custom, fine-grained, and efficient styling solutions.