They are the practice of the sravakas (voice hearers, desciple), hinayana (though not Theravada) and not the practice of the Bodhisattva, so it is ignored, as not worthy of practice.
Mahayana views in Sravaka link
In the 4th century abhidharma work Abhidharmasamuccaya, Asaṅga describes those who follow the Śrāvaka Vehicle (Skt. śrāvakayanika). These people are described as having weak faculties, following the Śrāvaka Dharma, utilizing the Śrāvaka Piṭaka, being set on their own liberation, and cultivating detachment in order to attain liberation. While those in the Pratyekabuddha Vehicle (Skt. pratyekabuddhayānika) are portrayed as also utilizing the Śrāvaka Piṭaka, they are said to have medium faculties, to follow the Pratyekabuddha Dharma, and to be set on their own personal enlightenment. Finally, those in the Mahāyāna (Skt. mahāyānika) are portrayed as utilizing the Bodhisattva Piṭaka, as having sharp faculties, following the Bodhisattva Dharma, and set on the perfection and liberation of all beings, and the attainment of complete enlightenment.
According to Vasubandhu's Vijnanavada teachings, there are four types of Shravakas:
- The fixed
- The arrogant
- The transformed
- The converted (to "Bodhi" or Buddhism)
The transformed and the converted (Buddhist) are assured in the Lotus Sutra of eventual Nirvana.
SO SAYS MAHAYANIST....hmmmmm???