By page do you mean like your live website with the changes?

I've thought about this too and I think down the line the plan is to be able to attach screenshots to merge requests. However, as a reviewer you can also pull down the changes and test them against your production site locally. So you can alter between the main branch and the feature branch and compare the differences like that. The benefit of this over a screenshot is it lets you actually get to see something like the hover effect in action.