ERROR log level not very useful

In this task: https://jira.percona.com/browse/K8SPSMDB-725
we introduced log levels in operator logs, but I'm having trouble seen some errors when ERROR log level specified.
I have tried to specify wrong option for "apply", some wrong images set, invalid backups and no errors were seen in the logs.
It just doesn't seem to be useful, so I think we at least need to explain in the docs what exactly will be visible if this is selected if not change how this works.

All I got to see is:

I0819 09:27:55.258458       1 request.go:665] Waited for 1.00757372s due to client-side throttling, not priority and fairness, request: GET:https://10.92.0.1:443/apis/networking.gke.io/v1beta2?timeout=32s
I0819 09:27:58.303767       1 leaderelection.go:248] attempting to acquire leader lease test/08db0feb.percona.com...
I0819 09:27:58.315416       1 leaderelection.go:258] successfully acquired lease test/08db0feb.percona.com