The message gets buried; the page does not
You type the invitation into the family group, three people reply instantly, and by Thursday the details are five hundred messages deep. Someone asks for the address again. Someone else cannot remember whether it was Saturday or Sunday. This is how every WhatsApp invitation ages, and it is why the best version of one is not a message at all but a link to a page that stays put.
Build a baby shower invitation on My Joyfullday and the chat gets a single link. Every person who opens it a day or a week later sees the same date, the same address, and the same reply button. The confirmations land on your guest list as they arrive, so you learn who is coming from the list, not from scrolling back.