The primary advantages are:
1. It gives a clear, decisive affirmation that so-and-so should be PM/P.
2. The PM/P are answerable to the citizenry directly and not the party elites or party members who elected them party leader (ironically party elections don’t use a FPTP approach).
3. It gives the PM/P a mandate from the whole country/province for the common good, not a partisan good for just a party.
4. It makes it easier to separate the legislature from the government.
5. It avoids the uncomfortable results under a FPTP system that leaders are not supported by the majority of the citizens.