According to the definition of Kabbalah given by Kabbalist Yehuda Ashlag, (Baal HaSulam), the wisdom of Kabbalah…
…is no more and no less than a sequence of roots, which hang down by way of cause and effect, in fixed, determined rules, interweaving to a single, exalted goal described as, "the revelation of His Godliness to His creatures in this world."
In plain English, this definition can break down to the following:
Kabbalah is a method by which any person can attain a higher level of reality.
It is important to note that it is a method, an empirical method, not a belief. Also, any person can study it, regardless of race, gender or nationality. "Attainment" means a clear perception and sensation, not an idea, theory or philosophy.
The higher level of reality that one attains through correct Kabbalah study has been given many names. As you can see in Baal HaSulam's above definition, he uses the words "His Godliness" to define the higher level of reality. You will also find words in Kabbalistic texts such as the "Upper Force," "Upper Light," "the Creator," "Nature," "God," "the Lord" and "the King," all describing that higher level of reality.
What do these terms define?
They define a quality of bestowal and love, which is the source of everything that exists in reality. This quality is also defined as a desire to bestow, often cited as a "will to bestow."
Opposite the higher level of reality is us in our current level of reality, called “this world” or “our world.” As the quality of the higher level of reality is bestowal, opposite to it is the quality of reception, also called the "will to receive." That is the quality of what is called "the creation" in the wisdom of Kabbalah, or in Baal HaSulam's above definition, "the creatures."
Therefore, the benefits of learning Kabbalah are the benefits that come from attaining the higher reality—revelation of the Creator, access to the quality of bestowal—while living in this world.