Two practical advantages set Grand Cayman apart. The first is orientation: Seven Mile Beach runs along the western shore, which means the sun sets directly over the water in front of the resort strip. Most Caribbean beaches do not do this, and it is the single biggest difference between a ceremony that ends in golden light and one that ends in shade.
The second is administrative. The Cayman Islands are known for a fast marriage licence process for visitors, without the multi-day residency requirements common elsewhere in the region. Combined with a heavily developed tourism infrastructure and English as the working language, it removes most of the friction that makes destination weddings stressful.
The trade-off is cost. Grand Cayman is among the more expensive islands in the Caribbean for accommodation and catering, and that should be factored into a guest list before invitations go out.