I did DofE Gold through school a very long time ago.
Like your DD, I had an activity every night already, and I did use some of those to 'tick the boxes', though I also had to add some volunteering and over the years I added new sports and skills as I was discouraged from using the same skills/sports for Bronze, Silver and Gold.
Through DofE I managed to become a certified scuba diver, completed an aerobics course, learnt to dive (from a board), spent 12 months mentoring a younger girl with special needs, completed a first aid qualification, and of course all the stuff you learn through expedition (camping, cooking, independence, relying on a team, basic first aid in the field, working with others under pressure, planning, map reading, compass reading etc etc). Despite having a lot of activities before I started DofE, there is no way I'd have learnt those things, or been as equipped for life after school, without DofE. It was brilliant.
The fact you get to spruce up and visit the Palace to receive Gold from the Duke himself makes a young person feel very proud of what they have acheived, and recognises the effort and commitment that is neede to finish Gold level.
I would encourage anyone who is thinking about DofE to give it a go :)