No wonder, it's either strong bias from people working in a tracing vendor, or outright a sales pitch.
It's totally false though. Each pillar - metrics, logs and traces have their place and serve different purposes. You won't use traces to measure the number of requests hitting your load balancer, or the amount of objects in the async queue, or CPU utilisation, or network latency, or any number of things. Logs can be more rich than traces, and a nice pattern I've used with Grafana is linking the two, and having the option to jump to corresponding log lines from a trace which can describe the different actions performed during that span.
They asked me to enable tracing for 30s (we had Chrome extension, that sends some URL common parameter that enables in your web server full tracing (100%) for some short amount of time), and then I did some operations that our internal customers were complaining.
This produced quite a hefty tracing, but only for 30secs - enough for them to trace back where the issue might be coming from. But basically end-to-end from me doing something on the browser, down to our server/backend, downto their systems, etc.
That's how I've learned how important it is - for cases like this, but you can't have 100% ON all the time - not even 1% I think...
As for the numbers, that's why all tracing collectors and receivers support downsampling out of the box. Recording only 1% or 10% of all traces, or 10% of all successful ones and 100% of failures is a good way of making use of tracing without overburdening storage.
Definitely not the case, and, in fact, probably the opposite is true. In the era of microservices, metrics are absolutely critical to understand the health of your system. Distributed tracing is also only beneficial if you have the associated logs - so that you can understand what each piece of the system was doing for a single unit of work.
Ehhh, that's only if you view tracing as "the thing that tells me that service A talks to service B". Spans in a trace are just structured logs. They are your application logging vehicle, especially if you don't have a legacy of good in-app instrumentation via logs.
But even then the worlds are blurring a bit. OTel logs burn in a span and trace ID, and depending on the backend that correlated log may well just be treated as if it's a part of the trace.
