In Raipur, on July 11th, (1944) Baba gave an explanation on the powers of yogis (siddhis) compared to spiritual powers:

Through different yogas, one can attain strange, occult powers such as walking on water, talking with persons who are at a distance, becoming immune to snake venom through chanting mantras, et cetera. These powers, attained through yoga, control different vibrations, which have different effects. Each yogi controls one particular vibration through which he is able to perform certain feats impossible for an ordinary human being.

But the peculiarity of this yogic power is that it can control only one particular vibration. So that a yogi who, through his control of a certain vibration, can walk on water, can do nothing else. Likewise, one who can nullify the effects of the poison of a snake bite, can do nothing other than that. All these different powers attained through yoga practices are phenomenal, and hence transient and unreal. These have nothing to do with spirituality or spiritual powers, which are already latent in all, but manifest only in a few select ones who have realized the Self.

All life depends on certain subtle vibrations [pran]; their connection is more universal through the ether [finest gas]. (1) For instance, a yogi wants to obtain a certain connection to something which he desires. Just as there are infinite varieties of things in the gross world, so there are an infinite variety of things in the subtle realm. A yogi gets hold of one of these things [powers] and gains control over the vibration pertaining to that particular thing. The spiritualists – true spiritual aspirants, saints and masters – do not indulge in these petty playthings, because once Realization of God is attained, all powers come to him and emanate from him. It is all bliss which he himself experiences, and that bliss permeates everything and flows from none other than himself.

(1)  Gas in its finest state, one discovers in the mental world as Tej. Gas in a very fine state, one discovers in the subtle world as Pran. The vibration of ether, gross gas in a fine state, one discovers in the gross world through deep concentration. A yogi who attains the vibration of ether does not need to eat gross food, and the ether-vibrations help him to maintain his body. A yogi can thus live on ether alone. Similarly, poets, writers and artists attain vibrations of subtle inspiration temporarily; from the subtle world inspiration comes to them and they feel inspired to write poems, epics and create art; but they do not attain permanent experience which can only be experienced in the subtle planes through the transformation into subtle consciousness. Therefore, the yogis attain a different vibration (than the inspiration of poets, writers and artists) from the subtle world but can only feel one vibration and that too is temporarily – but in a more concentrated form as a power (form of energy). Although temporary, the vibration that the yogi holds in his own body can last a long time – centuries.

Lord Meher, Original Publication, Bhau Kalchuri, Vol. 8, p. 2959.