I agree with Tailwind's stance on this. You really don't need @apply if you're breaking things down to smaller components. I often see people have things like <ul><li className="long_list_of_classes">text1</li><li className="long_list_of_classes">text2</li>...</ul>. This is where I think we need a linter to warn against things like that. Make those <li>'s a component!
I have bern heavy Tailwind user from before v1.
It actually doesnt matter where you make the class grouping. You can make it in your templating language or you can make it in @apply. I prefer @apply because the same grouping can be reused if done correctly. @apply is great.
The reason they are discouraging @appply is because its hard feature to implement and many people dont understand how it works so they get to problems and create issues. It bothers Authors so much they have always been considering taking @apply out but i think they know big chunk of the userbase would leave to different similar project.
