Check this
wiki page[
^] to know about Crosstab.
The purpose of the Crosstab report is to generate a matrix like report for making sales reports, summary reports, etc.,
Let me ask you a question. How could you do the same report if crystal reports doesn't have CrossTab report option?
Can you do that?
No.
The End.
OR
Can you do that?
Yes.
Agree, but why reinvent the wheel when you have an option?
Using Crosstab option, it's simple to make a summary report within minutes. All you have to do is just map the rows & columns for reports.
FYI
Cross Tab Craziness in Crystal Reports[
^]