Normally I would agree, but there is one further consideration: Quatronia might be sending a sizable force to capture the city themselves. But I'm still not sure that HUSch's other proposal (raze the city, denying everyone Pyramids) is a better option.
Raze the city is just out of question.
But let's examine the possible scenarios:
a) we take the city, using the spy *this turn* for a successful (?) revolt
a1) we can disembark our units in Omaha Beach and take the city probably losing only the first attacker, or sacrificing one or both siege for the first attack. Siege are almost useless in defence. The units in Gold city cannot reach the invaders (us) since they have only 2 moves (no Engineering yet).
This will let us with 2 units in Omaha Beach, ready to be wiped and 4 units in the Pyrs City. They can easily take back the city in a couple turns.
a2) we attack amphibious: suicide, even if we lose only 1 unit they will take back the city in a breath, the winners will be heavily injured. And we can't use siege from the ships.
Net result in case a):
- 8 units lost,
- a handful of gold gained for the conquest
- a city ready to be easily taken by possible "allies" close enough to take advantage of the weakened city and Mav's units (surely they will have some losses and their units will be injured)
b) we just keep the galleons around the island, waiting for reinforcements
b1) no "allied" ships will arrive, we can take our time and attack when we're ready not only to conquer, but to keep the entire island.
b2) one or more "allied" ship/s will arrive: depending by the forces they can
field, we'll decide the best short-term strategy.