1. It's works extremely well with the current component-focused UI frameworks (react, svelte, etc). Subsequently, the verboseness that is often a complaint isn't an issue at all, but a feature.
2. Does everything out of the box, and very easy to customize.
3. And, most importantly, it allows for easy art direction. Does one button need to be a slightly different size or color for this one specific element? Chuck an extra modular class on it. No need to build a complex cascasding or edge cases. (Shout out to `tailwind-merge`)
Point 3 for me speeds up production work immensely. Also, not being in JS has shrunk bundle sizes by a small amount, which is always welcome in this era.