It’s a cloud service - so you can call out to it from anywhere you want. Just don’t ship your credentials in the app itself, and instead authenticate via a server you control.
> server-side rendering for each request in V8 might be more expensive to host than client side rendering in V8?
Expensive not in money terms, but in user experience.
Also: if you are doing e-commerce, 100ms added latency can cost you 7-8% in conversions. Spending 5% more on hosting to do SSR just makes economic sense.