I watched a "Master Beekeeper" type one summer, and I am convinced a scale can tell you a great deal for researchers and academicians. The masterkeep's two scales were on a grant from the state ag college to gather data on fan driven hive cooling systems.
Most folks here more like M.A.S.H. units of beekeeping when the buildup and flow are on, and with multiples of hives have little time for expensive (and fragile) toys.
I apologize if that came across harsh, tbelo. Data like daily hive weight-- especially when you are experimenting with different techniques-- is fascinating and ultimately necessary to research. Most of us here just don't have the luxury to deal with it.
While I have a few mature hives that throw off $500 a season, with annual hive loss/turnover running 30-50% in the US, most do not, and some are doing well just to establish for the next year. If I am going to put a scale under a hive (much less several), someone else is going to have to buy it. Exchange rate this morning is 1us:1.06er.