You're correct on all points. I should not have used the word "outperform" and should have said a simple cache could be sufficient. If for example you know you have more than enough memory to cache all items you receive in 60 seconds and items strictly expire after 60 seconds, then a sync.RWMutex with optional lock striping is going to work just fine. You don't need to reach for one of these libraries in that case (and I have seen developers do that, and at that point the risk becomes misconfiguration/misuse of a complex library).

Yeah, I basically agree with that.