Imagine you're sampling successful traces at, say, 1%, but sending all error traces. If your error rate is low, maybe also 1%, your trace volume will be about 2% of your overall request volume.
Then you push an update that introduces a bug and now all requests fail with an error, and all those traces get sampled. Your trace volume just increased 50x, and your infrastructure may not be prepared for that.
Imagine you're sampling successful traces at, say, 1%, but sending all error traces. If your error rate is low, maybe also 1%, your trace volume will be about 2% of your overall request volume.
Then you push an update that introduces a bug and now all requests fail with an error, and all those traces get sampled. Your trace volume just increased 50x, and your infrastructure may not be prepared for that.