Śaṅkara-sampradāya, they perform very austere penance and principles. They take three times bath at least, three times. And no clothing; simply one loincloth, one . . . and their possession is one loincloth and one wooden water pot. That's all. Nothing more. And they will lie down on the floor. So they are strict, I mean to say, renounced order is very strict. So they perform austerity. So Bhāgavata accepts their austerity. Āruhya kṛcchreṇa paraṁ padaṁ tata. By their severe penances and austerity they come to the supreme position.
Supreme position means to come to the point of realization of Brahman. Impersonal realization of Brahman, that is not also a joke. It may be impersonal, but that position is very high. That is accepted. That Vaiṣṇavas, or the personalists, they also accept, "Oh, their position is very high."