Seats and couches
The last of the eight Precepts and the ninth of the ten Precepts say that one should abstain from using high (uccā) or large (mahā) seats and couches (A.I,212). The Buddha asked his lay disciples to sleep on a mat on the ground during uposatha days (A.I,215).
Of course, it has nothing to do with morality.
The other Precepts, including the one about seats and couches, are ways of behaving that can assist in calming the mind and shaping character. In ancient India, and even in the modern world, sitting on an elevated or grand chair was a sign of power and status.
Monarchs, judges, lecturers, managing directors, the speaker of parliament, etc, all have special high seats.
To practise the eighth Precept is to relinquish, not display or take advantage of one’s social status, at least for a day. Practising the eighth Precept is about modesty,diminishing the ego and not ‘putting oneself on a pedestal.’