The more we concentrate on the transcendental form of the Lord, either on the lotus feet or on the calf or on the thighs or on the chest, the more we become purified. In this verse it is clearly stated "as and as the intelligence becomes purified," which means as and as we become detached from sense gratification. Our intelligence at the present moment in the conditioned state of life is impure on account of being engaged in sense gratification. So the result of all meditation on the transcendental form of the Lord shall be manifested by our detachment from sense gratification. Therefore the ultimate purpose of meditation is purification of our intelligence.
Those who are too much engrossed in sense gratification cannot be allowed in the matter of arcan to touch the transcendental form of Radha Krsna or Visnu Deities. For them it is better to meditate upon the gigantic Virata Rupa form of the Lord as it is recommended in the next verse. The impersonalist and the voidest are therefore recommended to meditate upon the universal form of the Lord, whereas the devotees are recommended to meditate on the Deity worship in the temple. So because the impersonalist and voidest are not sufficiently purified in their spiritual activities arcan is not meant for them.