Not sure if it's the case nowadays, but Go channels were historically around 4x slower than the equivalent mutex-based code. This is a Big Deal™ if you're writing performance sensitive code or in a hot loop.
Comparing a FIFO internally wrapped in mutexes and conds, designed to pass messages, to a single mutex makes very little sense. Of course a channel is slower than one of the bare primitives used to construct it!
The proper question to ask is whether your application (or your programmer) lends itself with the CSP paradigm or not, and whether this allows you to write simpler, more robust code.
Extremely performance sensitive code will always need to be written In lower level paradigms, using e.g. atomics directly - this doesn't matter for most code though. And to be frank, extremely performance sensitive code is past the capability of Go for quite a few reasons.
I've had the opposite happen, where because of mindsets like this, that it doesn't get properly discussed and going in blind having to deal with it later in a case where it was clear that it would matter.
