Yes mind is the only means of devotion, physical senses of the body can help in engaging the mind in spiritual practice but it cannot help one attain the fruits of their devotional practice.
 
The spiritual law of God is that you will attain only that which you are attached to – whether it be spiritual or material, it will be according to the attachment of one’s mind, and not according to one’s physical actions.  Thus, if we are physically engaged in worldly activities, but keep our mind attached to God, then we will not have to bear the fruits of our physical actions. We will only receive spiritual results if we can develop a loving attachment of our mind to God.