Ghadwah is a morning departure; rawḥah is a departure toward the later part of the day. Either period can be highly valuable because of the purpose for which it is devoted.
أَوْ means “or”; the wording does not require both periods on every occasion. In مَا فِيهَا, the pronoun هَا refers to الدُّنْيَا—“what it contains.”
The contrast is with temporary worldly possessions. It does not imply that lawful work, education, or family needs are worthless; it emphasizes intention and the lasting value of deeds.