Are Pack 'n Play-style cribs safe for overnight sleep?

Community sources consistently say yes for the main playard floor of established brands like Graco, where the firm, low mattress is intended for safe sleep. The recurring caution across r/Buyingforbaby and r/Mommit threads is that elevated bassinet and 'sleep nest' attachments often have low weight limits (frequently around 15 lbs) and that some detachable upper baskets are not rated for unsupervised sleep—always check the manual for your specific model.