Unless I'm missing something you don't install a website you simply open the index.htm.
If it were a presentation, you would open it.
If it were a PDF, you would open it.
If it were a website, you would open it.
No installation.
There's also the presumption that the site will be viewed at the same location it was downloaded. Maybe they need a portable solution to be used in premises with no Internet connection.
Using a portable site isn't clumsy at all.
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