Kai is correct that Lime-Softening is very similar in its results, excepting that if you take the pH during lime softening up to about 11 you will also drop out some magnesium. That is another possible advantage to lime softening. I agree that it is a better way than boiling, but I actually don't know when the advent of lime softening was. I'm pretty sure some of my water treatment text books have that information, but I couldn't find it now. I'm not sure if Dreher or other brewers at that time would have had that knowledge.
Remember, either of these treatments can only remove the temporary hardness components and not the permanent hardness. If the water has bicarbonate, its got temporary hardness. The sulfate and chloride contributes to permanent hardness.
Oh, and I agree with Kai that using the aquarium test kits for GH and KH are perfect for assessing what goes on with either treatment.