The hard part of fiber-reinforced-concrete and cement is getting all of the fiber embedded, which usually will involve a skim coat, to fully cover the fibers.
The nice things about typical ferrocement boat construction are the known strengths and weaknesses, allowing for calculated design parameters, the relative ease of construction, the cost-effectiveness and near-universality of supplies, etc.
One big disadvantage is the visual-inspection only. Unless it is near failure, you may not be able to detect corrosion, so extra care, prep., and handling in the construction process is mandatory, to produce a realistic useful-life.
Geopolymer cements/concretes have the advantage, in that they are able to be X-Ray examined, for a more accurate assessment, they prevent the migration of water through the hull, and, prevent corrosion more effectively. The nice thing about Basalt rebar, despite its’ current cost, it does not corrode and does not really have to be mined. Basalt, itself is a common natural material.
In the old forum, I was a big proponent for ferrocement. I think the evolution to geopolymer is astounding and well worth exploring, for its’ potential, and it uses the same basic, known techniques, so it’s more about adjusting the technique for the new properties, rather than a whole new mystical experience.