For some, it may be the only option.
Windows Mobile devices synchronize out of the box with Exchange Servers
using a tool called Outlook Mobile Access (OMA).
On a default
installation of Exchange Server 2003 and higher, OMA is installed along
with OWA. Unfortunately, the mere thought
of accessing Outlook data via a mobile device scares some IT
departments, many of which in turn disable this functionality because
of the unknown. Others may disable this feature simply because they
"only support Blackberry devices".