Same reason as any other LAN party though. Like, you (average HN user) probably would wonder what's in the treehouse. But show it to a 9 year old and they'll say: fuck yeah, awesome treehouse, I want one. Filling it with activities comes later.

DN42 (https://dn42.network/) is kind of like this but public, mostly used to play with networking technologies though you could also use it to make a virtual LAN party.

Note: If you do, you should probably check the paths your traffic takes and get consent of everyone on the path, since most people expect to mostly pass network-control traffic and some nodes have very limited bandwidth. Fortunately, AS-paths in DN42 are usually quite short. If all your LAN party traffic is confined to your own network then obviously it's not a problem.

If you built one of these you could also connect it to DN42 as-is, being aware more people will be able to access your network if not firewalled.