The framing as a framework replacement did the standard a disservice. As a distribution format for shared UI it is genuinely useful.

Where they win

An organisation with Angular, React and a legacy server-rendered application can ship one button, one date picker and one set of tokens. Nothing else offers that. The component keeps working when a team upgrades a framework, which over five years is worth more than any authoring convenience.

Where they struggle

• Server-side rendering is still awkward compared with what frameworks do natively.
• Form participation needs deliberate work to behave like a native input.
• Passing anything richer than a string across the boundary means properties and events rather than attributes, and every consuming framework does that slightly differently.

Use them for the leaves of your component tree. Keep the application logic in the framework the team knows.