Informal backlog refinement doesn't typically happen in a distributed setting. The need for a well-defined "Definition of Ready" is more prevalent in distributed teams because ad hoc refinement can prove difficult in a remote environment.
When it comes to distributed teams, an agreement needs to be made ahead of time on what feature development readiness means. This agreement is the "Definition of Ready". A "Definition of Ready" is crucial to operations because there are circumstances that need to be systematically addressed every time a new backlog item is considered ready for development.
For example, the Product Owner may not consider some of the needs or preferences of the team in the feature description. Once Sprint Planning is held, development may end up resisting the start of features if their inputs are not considered. Conflicts such as these can be mitigated with the implementation of an extensive "Definition of Ready".