Pros and Cons of BW and data sources integration directly from data sources

Hi,

We are trying to justify investing in BW for building our reporting platform, or directly feeding data from SAP ECC, Microsoft Dynamics CRM, etc. Besides the usual benefits that a DWH brings about (OLAP, ability to slice and dice historical data, as well as storing consolidated data), what are the other benefits? And how do we directly source the data from ECC and our CRM systems to do sales reporting and financial reporting using Xcelsius? Does BO 4.1 come with connectors to directly connect to these data sources? Or do we use Infosets, etc?

Would really appreciate some inputs on this.

Thanks

Pallav