Today, I was faced with a real-life example of why Technical Writing matters.
Our dental insurance cards are printed in a ALL-CAPS, sans-serif font. That matters because:
Capital Letter I looks exactly like Numerical 1
Numerical 0 looks very much like Capital Letter O
When asked to share your member number, one has to study the rest of the member card to clarify 1s from Is and Os from 0s.
A Tech Writer would catch this as a problem during the card’s design and would insist on a distinctive font that uses serifs for the I and 1 as well as wide capital Os and “computer” 0s. Anyone with an eye for fonts would save the insurance companies’ customer service lines a lot of wasted time in deciphering their non-specific characters with customers on the phone.
Consider, too, not every font renders these characters with distinction:
8, B –or even– S, 5
Use your Technical Writers and staff designers. You will find a balance between a font that fits on the card, one that is legible to customers, and one that is attractive, too..
 If you are using Internet Explorer, you may not see the symbol for zero. IE does not play nice with the Internet and simply can’t do what other browsers can. Consider Firefox or Opera, instead.