使用XSL呈现整个网页的好处/缺点

I am in the preliminary stages of planning a project with a client to redo their current website. I took a look at their current site to see what issues they are currently dealing with and upon inspection I noticed that every page is being rendered entirely using XSLT. I am familiar with XSLT, I have used it to render custom controls that need to be refreshed often on the client-side, but never to render an entire page. I am in the preliminary stages of planning a pr