Since version 2012 financial dimensions are stored within a RecId together with other informations. Everything is fine as long as reporting takes place in the financial modules.
Some customers like to report material transactions with financial dimension information/filtering. Decoding the financial dimension from the recid in the materials transactions on the fly is rather elaborate and performance-consuming.
Whenever a customer wants reporting on the materials with financial dimension information a workaround would be to enhance the relevant tables with fields that store the financial dimension information in „plain text“ so that it can be easily evaluated. It would be nice to get a solution for this question in standard.