Which two benefits does using variables in DAX measures provide over using original expressions?

Using variables in DAX measures significantly enhances both performance and readability of the resulting DAX measure. When you define variables within a measure, they store intermediary results. This prevents the need to recalculate the same expression multiple times, which can lead to improved performance, especially in complex calculations. By calculating the value once and reusing it, you optimize the measure to execute more efficiently, thereby enhancing the overall performance.

Moreover, variables help improve the readability of DAX formulas. By breaking down complex expressions into simpler, named components, variables make it easier for others (and for you, later on) to understand what each part of the calculation is doing. This structured approach allows users to follow the logic of the measure without getting lost in long, convoluted expressions, ultimately fostering better collaboration and maintenance over time.

Although there are advantages to defining multiple measures that might be reused, the primary benefits of variables specifically lie in these two areas: performance and readability. The other options do not reflect the fundamental advantages that using variables in DAX provides.