"So what is the use of ODBC in accounting? Most (90%) of the small to medium sizes business have zero use for ODBC. Please educate me... why is this so important for a business?"
1. If it wasn't important, why is it a standard feature of the Windows app? It's part of the basic feature set there. Windows is 90% (probably more) of the accouting market and they HAVE this feature.
2. Have you ever WORKED with a small business? Who wants to enter their sales data into MYOB or Quickbooks? It's all done in FileMaker or other databases where you have control over the workflow and interface features, etc. Then the data is transferred to MYOB. Or reports are run in external apps based on accounting data.

Ever talked with MYOB people at Macworld or wherever? They've been claiming for years they're going to make application integration easier for the Mac. Oops, it ain't happening.