Adobe Flex - Business Objects Crystal Xcelsius: what's the difference??

We are currently building our 1st application with Adobe Flex and we discover more and more opportunities for this tool. I am sure we can build e.g. BI dashboards with Flex too. However, Business Objects Crystal Xcelsius is also sold as a technology for building Flash-powered dashboards. I also found information that it is possible that integrate Flex components in Crystal Reports. So I am a bit confused at the moment.

What exactly are the differences between Flex and Crystal Xcelsius, pro's and con's and why should there be a need to use both technologies or integrate custom made Flex components into Crystal? Is there a need for Crystal Xcelsius in our case? I am pretty convinced that we will be abe to build the applications shown in http://www.businessobjects.com/product/catalog/xcelsius/demos.asp with Adobe Flex too.

I am pretty convinced Business Objects Crystal Xcelsius is Adobe Flex / Flash based so I wonder why we should buy it?

Any input is very much appreciated!

kind regards

Angelique Heutinck