On the face of it yes it does seem strange, but after the Geneva trial proved that passengers were not 'canibalised' from either BRS or LGW, the decision was made to consider more substantial operations from the airport. This has been given priority status because the yield at BOH is considered to be lucrative.
BRS pax do not leak a great deal of passengers to BOH, and BOH potential pax leak more to LHR and SOU. (both very high yeilding airports)
of course it would be stupid of me to list my sources!