Data vaults could act as the central point for a series of other devices to be connected to them. This could include things like access terminals that allow multiple locations to all have access to the same vault(which might be useful for things like having one in the back room of a bar for employees to modify things, and one in the front for customers to see the list of events), or displays for showing images(thank you @svetlana for the idea!), or potentially wireless connections that allow portable e-notes to connect to a data vault(given they have the right module). This would allow players and factions to create their own data networks, modifying their building to suit the needs of the people there, and offer vulnerabilities in this network for other players to exploit. A junction box might hold connections to a building's cameras, but it might also hold connections to their data vaults.
The above idea might be a bit much to implement, but I hope it gets ideas for making data systems multi-part, with networks to go with the new vaults. If none of the above could be implemented, I'd still like to see data vaults themselves as something players can purchase and install.