I will give you couple of reasons.

I have tried most of the lime available in the US and had everything: detachment, pits, fluorescense, cracks. In fact I got so good at it that with bagged CA HO2 I can make cracks "to order" big ones, medium sized, strait, hairline, and superfine ones also.

With Italian lime you need to take a juckhammer to take my fresco off the wall. After working on 400+ sq. feet wall with Italian lime, my plasterer refuses to touch any other lime even during our workshop in practice plaster class.

I have spoken with GenLime three years ago and they did not have the stuff then. I talked to dr. Curtis yesterday and waiting for the sample of their new product, but it will still take a few years of testing in my studio (if I can talk my plasterer it it) before I would be confident to use it on a project.