'Why one should try to understand Bhagavad Gita'

Those who really seek the Absolute Truth come to the understanding that Krsna is everything (vasudevah samam iti). Such great souls are very rare. Nonetheless, if one studies the entire Bhagavad-gita as it is, Krsna is very easy to understand. The Krsna consciousness movement is just trying to make Krsna known all over the world as the Supreme Personality of Godhead (krsnas tu bhagavan svayam [SB 1.3.28]). If people take this movement seriously, their lives as human beings will be successful.
Srimad-Bhagavatam 7.10.70

So where is the difficulty to understand Krsna consciousness? Everything is there in the Bhagavad-gita. If you diligently study and try to understand, you remain fully Krsna conscious always. Everything is there. What is my position, how I am working, how I am dying, how I am getting body, how I am wandering. Everything is detail is there. Simply one has to become little intelligent.
Bhagavad-gita 2.21-22 -- London, August 26, 1973

But still, as it is suggested in the Bhagavad-gita: yad yad acarati sresthah. Yad yad acarati sresthas tat tad eva itarah janah [Bg. 3.21]. If the so-called leaders, they become Krsna conscious, they understand the philosophy, then others will follow. As, at the present moment, because the leaders are foolish, blind, they have no spiritual knowledge, all the population of the world becomes godless. Therefore our appeal is to the leading personalities to understand this Krsna consciousness movement. Try to understand its philosophy, apply in life, and try to distribute this knowledge. Automatically others will accept. Sa yat pramanam kurute lokas tad anuvartate. If Krsna consciousness movement is accepted by the leading personalities... Why they shall not accept unless they are ignorant and less intelligent? Everything is there. The Bhagavad-gita is left for this purpose. It was instructed not to Arjuna, but to the whole world, in the midst of Battlefield of Kuruksetra. So the whole world is a battlefield now. They should learn the teachings of Bhagavad-gita and thus become happy within this world.
Bhagavad-gita 2.17 -- Hyderabad, November 22, 1972