Sridhara Swami's Commentary
The question may be raised that if moksa or liberation from material existence leads to the cessation of enjoyment of the senses how can it be considered as desirable for humans? Anticipating such a doubt Lord Krishna reiterates that pleasures which come from contact with the objects of the senses can be a source misery even at the time of enjoyment. These pleasures are difficult to gain because they are fleeting and fickle. They are difficult to maintain because they are wanton and frivolous and they are difficult to sustain due to competition, jealousy, reprisals, etc. Because all pleasure is temporary having a beginning and an end; the discriminating individual does not become attached and hanker for them.
Bhagavad-Gita