> But there still is a little bit of server load, whereas front-end has 0.

That's true. OTOH, using a front-end framework has downsides, too. You have another framework involved, a big pile of JS that must be downloaded, more build tools, maybe you need to render server-side anyway for first page load...

> I'm not really sure how much of a savings we're talking about here (server side vs. client side rendering)

Yeah, me either. I think "what's the easiest way to get & maintain the desired user experience?" is probably the best question.