Error, warning or tip – what's in a name?

The Accessibility Checker in Word classifies each issue as an error, warning, or tip. But what do these mean? Is one more important than another?

First, the definitions:

• Error. Content that makes the document difficult or impossible to read and understand for people with disabilities. Example: Non-text content has alt text.
• Warning. Content that in most (but not all) cases makes the document difficult to understand for people with disabilities. Example: Sufficient color contrast between text and background.
• Tip. Content that people with disabilities can understand but that could be presented in a different way to improve the user’s experience. Example: Document uses heading styles.
• Intelligent Services. Content that is automatically made accessible by AI, and that you should review for accuracy and context. Example: Auto-generated alt text.

Second, the importance:

All issues should be addressed. It doesn't matter what category they fall into. One flaw may be more fatal than another, but they all contribute towards making a document difficult for someone to read and understand.