A few local details...
Posting as AC because of insider knowledge of the hospital in Craignure.
The hospital is very small, normally just five beds (three real beds and two A&E trolleys), most of which are usually empty. Since the panic began they have had access to a few extra beds just in case, and one of the original beds has become a dedicated isolation bed.
CalMac reduced the ferries to an absolute minimum very quickly, to isolate the island. There have been two confirmed cases of the virus on Mull: the first was an islander who came home from holiday slightly ill, recovered in hospital and went home. The second was a man who drive his family up from England to isolate on Mull, fell ill, was treated at Craignure and was then moved to Oban where he sadly died.
The BBC have been reporting that these drones were to rush urgent supplies of PPE to the hospital staff. There has never been any shortage of PPE at the hospital and they have plenty of supplies. The staff think that they may be intended to send Covid tests to a lab in Glasgow via Oban railway station (next to the ferry terminal). Any tests carried by drone will need to be transported from wherever the drone lands and transported down to the station anyway. It is just possible that the drone may save a few minutes on an overall journey of several hours, but only if the train timetable fits.
The staff don't understand the need for these drones as they don't have, and don't expect to have, any need for urgent transmission to the mainland or supplies from the mainland. The weather in that area means that the ferries will be running long after the drones will have been grounded, so the ferries are a much more reliable option.