It takes some extra work to produce a visually appealing page that a screen reader can easily read and navigate after the style sheets are ignored by Jaws. It requires careful planning to design a page with multiple columns (menu column on the left, main content in the middle, additional information on the right) and organizing it so a screen reader can skip to the main content without listening to menu choice after menu choice on every page but still looks appealing to sighted users after the style sheets are applied.
W3C guidelines don't tell you if common acronyms like URL, IANAL, CDMA, IMHO, or DMCA will be read letter by letter or pronounced as a word. Even little things like spacing or placement of periods inside or outside quoted material can cause the content to be spoken differently by JAWS. W3C page scanners will catch obvious mistakes like missing ALT tags and missing column headers, but having the designer actually listen to their page certainly improves it.
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