It can be built with simple wood working equipment for a fraction of the cost of a Langstroth hive. The economy of the top bar system applies to more than the construction of the hives. Each colony is a unit. There are no extra boxes to be warehoused during the off season and protected from rodents and moths. This means that less building space is needed for a topbar operation.
Less petroleum is needed too.
The topbar hive can be moved but it is not as easily moved during the production season while new fragile combs are being built . This may well prove to be a blessed limitation, since many of the problems we now suffer as an industry resulted directly from the spreading of problems through migratory beekeeping. Less petroleum is needed to harvest honey too. Only the honey is taken from the hives. This is in sharp contrast to the system that requires boxes to be removed from each hive, taken to an extracting site, and later returned to the hives.