sva-gṛhaṁ prāviśan nṛpa
Here Bāṇāsura is described as ku-dhī (“having bad intelligence”) and ku-mati (“foolish”) because he completely misunderstood the actual situation. This demon was so arrogant that he was convinced no one could defeat him. He was delighted to hear that someone as powerful as Lord Śiva would come to fight with him and satisfy his itching for battle. Even though Śiva had said that this person would break Bāṇa’s flag and destroy his prowess, the demon was too foolish to take this statement seriously and eagerly awaited the fight.
At the present moment materialistic people are delighted by the many unprecedented facilities for sense gratification. Although it is clear that death, both individual and collective, is quickly approaching them, modern sense gratifiers are oblivious to their inevitable destruction. As stated in the Bhāgavatam (2.1.4), paśyann api na paśyati: Even though their imminent destruction is apparent, they are too blind to see it, being intoxicated by sex enjoyment and family attachment. Similarly, Bāṇāsura was intoxicated with his material prowess and could not believe that he was about to be cut down to size.