Go is a replacement for a certain subset of C/C++ projects that are I/O heavy, e.g. web servers. However the GC precludes it from many uses of C/C++, e.g. you couldn't write an AAA game in it, or a kernel, or a toaster.
Serving web requests with ephemeral workers introduces some new problems though. Generally efficiency in this space comes from pooling, reusing connections, multiplexing etc ...
Because GC will pause threads while requests are being served, this leads to latency spikes at the higher percentiles.
It introduces a whole distinct type of complexity into operating the server.
The latency of a request to your server is not just caused by the code that is ran to serve that request (which is how people intuitively would think about it), it can be caused by GC pauses that are happening because of the memory pressure caused by previous requests.