A feedback widget can help a person tell a team that something went wrong. It cannot reveal every barrier. Some people will not find the widget, will not have the time or energy to explain the issue, or will simply leave the service.
Feedback reflects who responds
A person who reaches the reporting channel is not necessarily representative of everyone who tried the journey. Treat feedback as evidence to investigate rather than a complete map of the audience.
Find barriers before launch
Learn about the people using the service, talk with them and test real tasks with varied participants. Review the points where someone must understand instructions, remember information, make a decision or recover from an error.
Give the team responsibility
Use tools to support research and issue tracking, while keeping judgement and accountability with the product team. A user should be able to report a problem without having to diagnose it for the organisation.