Hi there,
That’s a great video and I like the design of the site so far!
While I’m not familiar with the theme itself, I can understand their point of view in that if it’s not built with the quickview option then it’ll take some work to add that.
In short, it is possible to add that but it would require some customisation in the form of (1) Add the button, (2) triggering the lightbox/quickview modal, and (3) populating it with a specific section of the single product page.
The underlying changes would include PHP/HTML to add the button, CSS to style the button and JavaScript/jQuery to trigger the lightbox/Quickview modal.
In short, it is possible but unless the theme caters for that out of the box, it would need to be added through custom coding from a web developer (or one of the experts listed at https://woocommerce.com/customizations/)