This verse is commenting on the development of Āsana
as a foundation or accessory for more subtle practices.
Better not to confuse the vehicle with the direction.
I am reminded of a quote from Srivatsa Ramaswami:
“I studied with Śrī Krishnamacharya for a number of years.
I do not remember a single Yogāsana class which did not have
a decent dose of Prāṇāyāma and Ṣanmukhi Mudrā in it
and short prayers to begin and end the session.”