In our agency augmented HTML (Htmx/Intercooler, AlpineJS, etc.) is very useful for web designers, they can go further with interactions and behaviors while staying in a HTML/CSS environment. Also it helps a lot in the communication between the design and developer teams, because there is a lot more understanding of what's going on.
That's great to hear and one of the big benefits to an HTML-first architecture: it's much easier to understand the entire stack, for feature development as well as optimization.
