Why do we build time dimension, what is the benefit of using the date wizard rather than building the dimension using the normal way?
Use the Date wizard to build a Time dimension and you will see the difference. Time dimension automatically creates lot of relative Time categories which the regular dimension does NOT. Those categories are extremely valuable for analytics.
I have no problem with the date wizard generated dim, but here we have a custom conformed time dim table we use for all our dates. It has all the items in the generated time dim. In addition, we have a few dozen different attributes on it, and can and often do build multiple alternate drill-down paths, e.g. year->quarter->month->day, fiscal-year->fiscal-quarter->month->day, etc.
So it just depends on what you need.