I understand your concerns but React/Vue SSR is such a hot topic because of targeting mobile devices. Its getting to the point that if you are targeting the mobile market AND using React/Vue it is assumed that you will be using their respective SSR technologies to offset the delay of rendering the entire page inside the client device.
A more frugal way would be to stick to EEx generated HTML and even handwritten CSS to minimize loading times with just a bare minimum of JavaScript. But many feel that the loss of interactivity is just not worth it.
Also outside of the Phoenix space the frontend is already taking on more responsibilities because of serverless technologies so combining SSR with React/Vue isn’t viewed as much as premature optimization but the cost of doing business with mobile customers.
