I work for a company that sells 802.11 gear and most of the clients I deal with set up ISPs with our gadgets. So, NO it's not just for LAN access, in fact the coolest part of 802.11 is the ability to set up your infrastructure easily in places where there is no high speed cable (DSL)service.
Don't give out advice you cant back up

Here is one of our products that ISPs use:
<a href="http://orinocowireless.com/template.html?section=m61&page=1406&envelope=97" target="_blank">Wireless router</a>