Concrete sealant vs spraying to cure a concrete slab
All of those methods do the same thing.
The sealant method is done one time, no additional sealant needed.
The water spray method needs to be done regularly, maybe every hour or so. The dam method has time involved for making the dam, but does not need to be maintained as much as water spray.
All these methods are done only after the last troweling is done and the surface will not be disturbed by anything placed on top of the concrete.