Why use logging when you already have tracing?
This might be a very naive question; but given that tracing seems to be a superset of structured logging, when would you want both logging (e.g Grafana Loki), and tracing (Grafana Tempo) as opposed to just Grafana Tempo.
Tracing is the what and logging is the why. Sure, you have the names of the methods for the spans, but do you have insight into the internals of that method in the trace? Probably not. Logging gives you that extra fidelity in a more human context.
Together, they are extremely powerful.
You want to know what's happened whether there is an exception or not.