There are different material perfections that a yogi can attain as by-products in the endeavor of yoga.
Those yogic perfections or siddhis include: 1) the power to become smaller than the smallest, 2) the power to become greater than the greatest, 3) the ability to fetch anything from anywhere in the universe and bring it to him, 4) the ability to perform all sorts of apparently impossible activities like walking on water, flying in air, making things appear out of nowhere and 5) the power to control the minds of others.
So, generally speaking most yogis aspire to achieve some or all of the siddhis or perfections which are all material in nature because they all involve the manipulation of the material energy of the Lord and have no connection at all with the spiritual energy. The tendency is, when an yogi achieves some mystic perfection or yogic siddhis then taking advantage of it, the Yogi goes out into the public and performs some wonderful activities believing it as the perfection of Yoga Practice.
Yoga practice is not meant for attaining any kind of material benefit or siddhi (perfection). These yogic perfections and peace of mind are by-products of the yogic process but are not the actual purpose or the final goal of yoga.
The real purpose of yoga is to enable one to end material existence and then attain the kingdom of God.
One who seeks an improvement in health or who wants any other material perfection or benefit is not a yogi. According to Scriptures. “Cessation of material existence” does not mean one enters into “the void,” [a theory that some transcendentalists promote]. This “void” is only a myth. There is no void anywhere within the creation of the Lord. Rather, the cessation of material existence enables one to enter into the spiritual sky, the abode of the Lord. The abode of the Lord is that place where there is no need of sun, moon. All the planets in the spiritual kingdom are self-illuminated like the sun in the material sky. The kingdom of God is everywhere, but the spiritual sky and the planets thereof are called param dhama, or superior abodes.
A successful yogi can attain real peace and can ultimately reach supreme abode. No one can reach the spiritual sky or enter into the kingdom of God without the proper understanding of plenary expansion of Almighty. Therefore a person working in the consciousness of Almighty is the perfect yogi, because the mind of such person is always absorbed in nature’s activities. In the Vedas also we learn, “One can overcome the path of birth and re-birth only by understanding the Supreme Personality of Godhead. In other words, perfection of the yoga system is the attainment of freedom from material existence and not some magical jugglery or gymnastic feats to fool innocent people.
Thus, the simple point, that the purpose of yoga is to enable one to end material existence and enter into the kingdomof God, is something that almost all the modern so-called yogis are completely ignorant of.
This is very valuable and important for those who endeavor to experience and realising the Reality within the Being.