As mentioned previously, the purpose of BCS is to provide a mechanism to retrieve and manipulate data stored in external business applications or systems. BCS can be used to embed remote datasets in your own applications, giving users a familiar interface to manipulate or view data.
For example, if you are a reseller of restaurant supplies, you may want to connect to the manufacturer or other wholesale distributors and import their data catalogs into custom applications that your employees use to quote and resell equipment to end customers. Using BCS, you can create connections to your suppliers' applications and render that data in your own applications.
Depending on the data source and external data configuration you need, BCS can be used to support create, read, update, delete, query (CRUDQ) operations.