The longer term measure of our Prāṇāyāma potential is determined by
our skilful efforts with all four components of the breath in Āsana.
For example can we maintain 18.104.22.168. in Parśva Uttānāsana or 22.214.171.124 in Mahāmudrā?
These days though, it seems that there is not much place for or interest in the use of Kumbhaka
and breathing practices, if used at all it appears to be mainly Cikitsā or about recovery,
or at best Rakṣaṇa or constitutional, rather than Śikṣaṇa and developmental.