Reflectance meters

[Gemjunkie]

Touted to be easier to use and certainly more attractive in the field due to the freedom from toxic, corrosive chemicals, as well as having a higher RI limit.

A dealer asked me, are they worth buying to take along on buying trips? The ads list a lot of gemstones that it can differentiate between that reasonable knowledgeable people really don't need a instrument for, like separating Morganite from rose quartz. Not a real world issue IMO. How practical is it?