Terrible Idea

Hate it!

Can’t modify output with filters, can’t easily override CSS, both in html output and CSS alternatives.

Adds HUGE bloat to CSS, especially if your theme already uses common frameworks like Foundation.css and Bootstrap.css. (.wp-block-button__link vs .btn)

– this is a ‘non-tech users’ framework – should stay a plugin to mitigate bloat from ‘tech’ users installations
– create docs and code in stronger abilities to integrate external css frameworks