This is it. Another thing with a webapp that someone might use regularly is that the JavaScript bundle that's sent down is cached and you likely won't have that

This is it. Another thing with a webapp that someone might use regularly is that the JavaScript bundle that's sent down is cached and you likely won't have that same load time every single time. However, if you have a landing page that someone might only visit once, then you want to optimize for as little JavaScript as possible, and in that case, just a pure server-side render might be best for that job.