Country domains or gTLD are the domains that are country-specific. For instance, the country domain for Australia is dot au, country domain for the UK is dot uk, country domain for the US is dot, us. etc. The primary purpose of country domain or gTLD is to rank on the local search. If your website caters to local people and if you wnat to rank for the local search, you need to use a country domain. For example, dot uk will rank easily in the UK compared to a generic dot com.