html, a href, mailto, email

question about html, a href, mailto, email

before
當我地要show email in html, we will type as below,
<a href="mailto:[email protected]">[email protected]</a>

but
最近我發現有d web, show as the following,
me[at]ques[dot]com[dot]hk

(que1)
為什麼會用 [at], [dot] 去代替 <a href="mailto:[email protected]">

(que2)
兩者有什麼好? 和有什麼不好?

thanks in advance,,,