Q: It is said in Aparoksha Anubhuti that hatha yoga is a necessary aid for enquiry into the Self.
Sri Ramana Maharshi :
The hatha yogis claim to keep the body fit so that the enquiry may be conducted without obstacles.
They also say that life must be prolonged so that the enquiry may be carried to a successful end.
Furthermore there are those who use some medicines [kayakalpa] with that end in view.
Their favourite example is that the screen must be perfect before the painting is begun.
Yes, but which is the screen and which the painting ?
According to them the body is the screen and the enquiry
into the Self is the painting.
But is not the body itself a picture on the screen, the Self ?
Q: But hatha yoga is so much spoken of as an aid.

Sri Ramana Maharshi :
Yes.
Even great pandits well versed in the vedanta continue the practice of it. Otherwise their minds will not subside.
So you may say it is useful for those who cannot otherwise still the mind.

~ From Be as you are book ~