House Bank & GL account

When I Build the House Bank (FI12) in the Bank Account Data I have to provide the corresponding GL account number this House Bank is using.

Also in the G/L account Maintenance Centrally (FS00) in the Create/Bank/Interest/ Tab, I have to Provide the House Bank and Account ID.

Why this redundancy? Why SAP needs the same information in two different places?

Appreciated.

YV