We are not all writing web apps. Some of use are in machine learning, NLP, signal processing, etc. where squeezing out as much performance as possible does matter.

In those fields Go is still weak. No autovectorization, no OpenMP, no direct CUDA integration, GC overhead, etc. Luckily, this can often be worked around since cgo is so good. One can write performance-intensive parts in C or C++, compile with the latest gcc or clang and link it with the Go code to drive it. This is often an understated advantage of Go compared to Java, where JNI calls are expensive. But the Go camp always advocate for porting everything to Go (because fast compile times).