Hatha yoga in the US has been altered to get people physically fit. It’s supposed to be a union of mental and physical into one, that’s the purpose of hindu yoga. Something like buddhist yoga has to do with simply mental yoga, and is perhaps much more effective I think.

Hatha yoga are physical postures (asanas) which you do
to keep yourself fit and strong and flexible. These postures
are preventive and curative too. They were evolved after
observing animals in nature. The founder of yoga is ofcourse
lord SHIVA but it was properly coded by sage PATANJALI.
Later on other sages also contributed to this. There are many
types of yoga to suit individual with different mind set or what
we call as temperament. For example an intellectual has
aversion to physical exercise for him/her it is RAJAYOGA
and for those who love physical for them it is HATHA YOGA.
For people with love and spiritual disposition it is
BHAKTI YOGA so on and so forth. Of these different type of
yoga the western world has adopted hatha yoga because
they clamour for physical strength and beauty. All in all
I prefer what swami Vivekanand said. Football takes you
closer to God than Bhagvad Gita. Ofcourse by this he meant
that one should be physically strong to reach Godhood,
though many Rajyogis do not agree to this. Personally as a
yoga therapist i believe everyone should be healthy and the
most natural way to health after walking and swimming is
hath yoga postures. Walking and swimming can be
impractical due to weather but having a mat of 6×3 is
sufficient to carry out postures all the 365 days. Hope this
satisfies your curiosity. Good luck and God bless. Cheers!
:o)