I mean, that’s one solution to WCAG 1.4.1, but not the only one. Per WebAIM’s recommendations[1] on the matter:
- Color is not used as the sole method of conveying content or distinguishing visual elements.
- Color alone is not used to distinguish links from surrounding text unless the contrast ratio between the link and the surrounding text is at least 3:1 and an additional distinction (e.g., it becomes underlined) is provided when the link is hovered over and receives focus.
Lots of options in there besides just slapping underlines on things. Could be bold where other text isn’t. Could just be a color that stands out enough against your text. Etc.
Contrast ratio between the link and the surrounding text is at least 3:1 sounds easy to achieve, but in practice it rules out almost every color, so it's a nonstarter in almost every case; WebAIM actually has a good article showing how few colors actually can hit a 3:1 ratio: https://webaim.org/blog/wcag-2-0-and-link-colors/.
Sure, you could make links bold, but no one does that for a reason: it looks ridiculous.
The thing that I find particularly egregious about that rule about it is how this doesn't even seem like it helps that many people. A screen reader user would necessarily know that an element was a link regardless of color, and even colorblind users are likely to be able to see that the text is lighter, even if they cannot make out the specific color, particularly if the color used isn't red or green.
- Color is not used as the sole method of conveying content or distinguishing visual elements.
- Color alone is not used to distinguish links from surrounding text unless the contrast ratio between the link and the surrounding text is at least 3:1 and an additional distinction (e.g., it becomes underlined) is provided when the link is hovered over and receives focus.
Lots of options in there besides just slapping underlines on things. Could be bold where other text isn’t. Could just be a color that stands out enough against your text. Etc.
[1]: https://webaim.org/standards/wcag/checklist