How successful was Hong Kong’s coronavirus mass testing programme?

After Hong Kong was blindsided by a third wave of Covid-19 infections, the city’s government joined forces with authorities on the Chinese mainland to identify carriers of the coronavirus. Hong Kong’s first Universal Community Testing Programme (UCTP) started on September 1, 2020, and ran for a fortnight. The citywide testing programme cost the Hong Kong government an estimated HK$530 million (US$68 million). It ultimately identified just 42 new Covid-19 infections among the 1.78 million people who registered to be tested. So, did the results justify the time and resources put into the project?