Concentration is the binding of consciousness to a single focal point.
Rishi Patanjali is dedicating the third chapter of the Yoga Sutras to Siddhis or Spiritual Powers which are also called Vibhooti (supernatural or extraordinary powers). These are natural phenomena of the mind once the mind is bound, meaning concentrated/absorbed , on a single internalized object of focus (whether that object is internal or external in the first instance) to the exclusion of anything else.
A concentrated mind, devoid of or unaffected by internal or external distractions, becomes a very powerful instrument of consciousness. It becomes the gateway to direct perception and experience of both the object and consciousness itself once the object is dissolved through further enstatic absorption.
Discipline, Dedication, Discernment, Detachment and Devotion (the 5 Ds) are the keys to your success on the Spiritual Path and not Siddhis (which are just effects).
Discipline = do your Sadhana daily with full awareness
Dedication = to Truth
Discernment = between the temporal / ephemeral and the Perennial
Detachment = serve others as your own self and develop equanimity in all circumstances
Devotion = to your Ideal (through Principle directly or indirectly through an Idol which contains or is representative of the Ideal)