There are a few reasons why CSS animations are often preferred over JavaScript animations:

Performance

CSS animations are typically hardware-accelerated, which means they can be smoother and more performant compared to JavaScript animations. This is especially true for simple animations like transitions and fades.

Ease of use

CSS animations can be easily applied to elements using CSS classes or pseudo-classes, without the need for writing JavaScript code. This makes it simpler and faster to implement and maintain animations.

CSS animations allow you to separate the presentation layer (CSS) from the logic layer (JavaScript), which can make your codebase cleaner and easier to manage. It also allows designers and front-end developers to work independently on animations without relying on backend or JavaScript expertise.

Browser support

CSS animations are supported by all modern browsers, including mobile browsers, without the need for any additional libraries or polyfills. JavaScript animations, on the other hand, may require additional code or libraries to ensure cross-browser compatibility.

However, JavaScript animations can be more powerful and flexible when complex animations or user interactions are required. It ultimately depends on the specific needs of your project.