Matsya Purana — Soma
मासश्राद्धं हि भुञ्जानास् तेऽत्येते सोमलौकिकाः एते मनुष्याः पितरो मासश्राद्धभुजस्तु वै //
māsaśrāddhaṃ hi bhuñjānās te'tyete somalaukikāḥ ete manuṣyāḥ pitaro māsaśrāddhabhujastu vai //
Those who partake of the monthly Śrāddha offerings surpass (the status of) the Soma-world (Soma-loka). Indeed, these Pitṛs—though described in human terms—are truly the enjoyers of the monthly Śrāddha.
It does not discuss Pralaya directly; it focuses on post-death states and the exalted standing of Pitṛs sustained by monthly Śrāddha, even beyond the Soma-loka classification.
It reinforces gṛhastha-dharma: performing monthly Śrāddha is presented as spiritually potent, directly nourishing the Pitṛs and elevating their condition—hence a key regular duty for householders (and by extension, a king as exemplar of dharma).
The significance is ritual rather than architectural: it highlights the efficacy and status-conferment of the monthly Śrāddha offerings, identifying the Pitṛs as the rightful recipients/enjoyers of that recurring rite.