I'm honestly surprised Nim is not the secret weapon of many start-ups. Nim is much more "open architecture" instead of pushing some "single, canned turn-key fits most users" solutions.
Having a juggernaut like Google marketing/pushing/subsidizing something might provide false as well as true peaces of mind. :-) { Such peace is a multi-dimensional concept. :-) }
I did move to Go from Python briefly for performance reasons but once I found Nim, there's just no going back. Simplicity might have real value in large projects but I just don't like my hands tied.
But I started using Go for the same reasons pointed out in parent and after being tired of changing Python code to C to resolve performance issues.
How about concurrency?
https://www.techempower.com/benchmarks/#section=data-r19&hw=...
Our particular design is a bunch of single-threaded apps on a message bus. Each app (network ingress/egress, data handling, relays, etc) sits on the bus, and can use async/await to do IO concurrency, but on the app level, there's no threading and no locking to observe.
Each app also has a erlang-inspired supervisor task system, where each task is just a async proc kept alive. It's proven to be very robust (from the standpoint of service availability) in the face of bugs or input validation mishaps.
Compiling to C really isn't relevant. "50 years of work on C compilers" is not at all relevant--languages that compile to LLVM get all the advantages of the optimization work.
The PoC was incredibly quick to manifest, and iterating on it had quickly proven itself as a good way forward.
Peace of mind was a judgment call. Despite being a rather sizeable project now, what we had back then was already very stable and reliable (even under heavy benchmark load) and there weren't any great unknowns souring making the call.
May I ask, did you consider Go and decided against it for any reason considering your requirements of quick development, cross-platform, interoperability are all guaranteed features of Go which should have given better peace of mind considering a production application?