Nafka minnah

Nafka minnah (Aramaic: נפקא מינה, lit. "emerges from it" ) is a Talmudic phrase used in analytical debates. It is often used in the phrase "Mai nafka minnah"? (מאי נפקא מינה), which asks, "What is the practical difference?"
Terminology.
The question "mai nafka minnah" is a way of testing the difference between two or more explanations for a given law, by investigating the different practical halachic rulings that would follow from each explanation. In other words, it means "so how do they differ in practice?"
It is contrasted with the question "be-mai peligei", which also means "how do they differ", but implies that the two views have the same practical consequences and that the difference is the intellectual process by which they are arrived at (for example, which Biblical verse is the relevant authority).
Example.
Examples of a "nafka minnah" abound, both in Jewish law as derived from the "Talmud", as well as in any situation that presents multiple rationales for a particular item.
To begin the "Shabbos" meals, "kiddush" is recited, followed by the eating of "challah". During "kiddush", the "challah" should be covered, which has led to a market for commercially available challah covers that are often beautifully decorated with embroidery or other designs. There are three reasons given for this practice:
Now that the custom to cover the "challah" has been established together with its three reasons, one could ask what the "nafka minnah" would be between the three reasons—how would a difference in practice occur as a result of one rationale being dominant over another? Each of the following bullets represents a distinct "nafka minnah":