Frontend development - perhaps more than any other kind of software development - is “what you see is what you get”. There aren’t a lot of ways a website can be invisibly broken.

Systems engineering isn’t like that. Vibe coders beware: A database could silently corrupt data, or have latent security vulnerabilities. It might have a badly designed query language that will be difficult to change later. But frontend code can be rewritten at will. It’s a perfect target for LLMs.

At the same time I have found LLMs far less competent at frontend because they don't seem to have any visual understanding of what a good website looks like.

"There aren’t a lot of ways a website can be invisibly broken."

??? Have you never debugged weird react state before??? Have you never used a nontrivial SPA before? Even the most simple react SPA has about a trillion states.

I don't really know how to respond to your statement than "no, they can definitely be invisibly broken."

The UX is what makes the users use the apps, systems, games, their phones.