Its a nice idea, but I wonder how well it will fit into their lifestyles when they first leave home?
My daughter hasn't lived at home for 10 years, and has only just now got a house of her own - a smallish semi. In those 10 years she has worked in 2 different cities and studied in the Uk and Canada, living in a variety of rented flats and shared houses. Space is always at a premium, and moving is best done with a heap of Lidl/Aldi 'bags for life' and IKEA blue bags which can be bundled up when not in use. Anything that needs 2 hands or 2 people to carry up stairs is a liability. My son is still in a small rented shared city flat. Likely a year or few before he gets established more permanently.
If they have plans to stay put then fine, if it's a peripatetic lifestyle maybe wait a bit. In either case, unless they have the luxury of spare space, maybe make it with a flat top so it can be used as a coffee table or have stuff stored on it.