How is it that when using "natural" units we drop the units themselves. I understand that you can arbitrarily change the magnitude of a parameter by choosing a new unit. For example Oliver R. Smoot is exactly 1 smoot tall. However, in natural units with [c]=[h/(2π)]=1 the "smoot" part is left off. Furthermore, leaving off the units allows us to conflate speed and action, which to me have always been different physical quantities. How do we justify this as it seems like its common practice?