Admittedly didn't read all the replies, but I have seen these threads before and know that opinions vary greatly. I do think the yay vs. nay when it comes to honeymoon funds is generational, because as someone in their early 30s, I have seen this more and more frequently among people my age.
DH and I got married in 2016. Like OP's daughter, we had lived together for 10 years and owned a house together for 4 years, so we had all the household items we needed. There were a few things that could use refreshing, so I created an
Amazon registry for that. An Amazon registry allows you to link items from Amazon, but also items from other web sites like Kohl's or Bed Bath & Beyond. We registered here for things like towels, dishes, etc. Not a lot of stuff, but mostly things you'd expect to see.
The
travel agency where we booked our honeymoon offered a service where they would print cards up that you could include with the shower and/or wedding invitations. It basically said "so and so has their honeymoon booked with us, if you'd like to give a gift towards it, please contact XXX" and listed our
travel agent name and number. When people called, they had three options: 1) Make a payment towards the balance of our honeymoon, and if they did, they'd be given a card they could put in their wedding card for us that showed how much they contributed 2) purchase a gift card for the travel agency which we could use towards the balance of our honeymoon or anything they sold their, like luggage or 3) purchase an excursion or add-on that our tour operator offered (i.e. snorkeling, a lei greeting at the airport, etc.). After the shower and wedding were all said and done, about 7 people purchased from our Amazon registry or gave an Amazon gift card, about 10 people gave us gift cards for our travel agency, and everyone else gave money.
Our honeymoon registry was a little different than those web sites out there, which just collect the money and take a cut of it. But I don't see anything wrong with any type of honeymoon registry, because no one is forced to contribute to it. If a guest is turned off by it, they still have the option to give cash or purchase an item they think makes a nice gift. There's no rules when it comes to gift giving, and registries are just meant to provide options for those who want to give the couple something they want or need.