SEO alone is a poor reason to use server side rendering. Services like https://prerender.io/ completely solve SEO for SPA's and can be as cheap as $0 per month. Compare that to dozens/hundreds of hours of engineering time spent setting up an SSR implementation; it is a no-brainer.

That service is like solving a problem with duct tape. The service could at any time disappear, introduce compatibility issues etc. It is a useful stopgap for some situations, but I would never want a high-traffic site with big uptime demands relying on a black box like this.

Especially when server-side rendering is so easy nowadays if you pick the correct stack.

This advice is badly out of date. Crawlers no longer respect the fragment meta tag, so unless the pretender is actually served, this service does nothing