Makes a lot of sense. The States of GCI can't afford to underwrite the Embraer and the required fleet of 6 Dorniers to replace the Trislanders.
This solution allows two Dorniers to be affordably acquired to protect ACI SOU whilst the GR financial contribution to SI's inter-island operating costs will help them, although the ATRs are frequently full so maybe the proposed two additional daily rotations will not be sufficient.
Aurigny benefits as well from the acquisition of the handling of all SI flights in JER and GCI, permitting SI to dump the dreadful service they get from Menzies and Servisair in the islands, each of whom gives a preferential service to Flybe. These handling agents will now be able to concentrate completely on providing BE with a service which has no distractions.
Good move all round for GR and SI