My own guess would be that what matters most for the frontend is UX (and accessibility).
So if you are able to properly evaluate the outcome, it is probably fine.
It will also depend on the type of frontend and its target complexity. From what I understand from your question, you would handle the backend and infrastructure so these do need higher rigour.
If you apply the principle of separation of concerns, the frontend shall be decoupled from the rest and may evolve on its own end. That means that you have some degree of freedom to test and fail the frontend without harming the rest of your project. Your end users may not like it much, but from a dev perspective, there is no "flaw".
Also consider that LLM training dataset and available data is huge about frontends, so it is way better at doing these.
Most likely it will work. It will also look very LLM-generated, “claudish”, and people will be able to tell that they are looking at the vibe-coded frontend.
Inside, there will be dragons: you will probably learn that all your CSS and JS are inline in your HTML, and that each page has its own implementation of the header and the footer, and other things like that, but if you don't plan to support it as a real product, you probably won't care.