Sure, "systems programming" has a variety of meanings. But, there are a lot of areas where C was the obvious choice in the past but Go might be a suitable replacement today. Areas where concurrency and safety is maybe more important than raw performance: Databases (and there are many now written in Go, including alternative types of databases like time series, key/value, etc.), servers, etc. I tend to consider those systems level, even if they are not kernel level or running on bare metal.

Obviously, if one defines "systems programming" more strictly than that, and only mean code that directly interacts with hardware or has hard realtime requirements (which also probably means it must interact directly with hardware), then Go does not make sense in that category. But, C has given up a lot of territory over the past several decades. When I first started programming, C was the language you used for writing almost any real application...if you weren't using assembly. That has changed a lot in the intervening years, and almost no one would think to use C for GUI apps today, for example.