Don't worry, Bob will stick around to serve food and drink.
Reserving the tavern for the low cost of just will phase players into a private version of the Arcantina, cleared of all other players and NPCs, except for the bartender himself. This includes any active quest givers and their portals, though consumables like Savory Deviate Delight and interactables such as the Undermine Electrician's Practice Board remain available to enjoy.
Players in the same group or raid are the exception, though it isn't automatic. Each player may speak to the bartender to opt into the private phase and can join or leave at their leisure, allowing the tavern to serve as a private meeting place for roleplay or any other desire. Think of it like going back to a private room, except its the whole tavern!
Each player needs to individually speak to Bob and pay the fee to join the private phase.
Bringing everyone back is as easy as speaking to the the bartender again to rejoin the public phase at no charge, though exiting and re-entering the tavern will also default to the public space.
Overall, this is a very minor but fun feature, which is perfect for roleplayers. While World of Warcraft has no lack of varied environments for players to explore, precious few of them are actually private outside of instances filled with enemies or player-created houses. Some players make use of older content, such as holding the Tournament of Ages at the now largely abandoned Argent Tournament Grounds in Icecrown, but this update to the Arcantina gives players another convenient space to congregate, which is both easy to access and can be made truly private.
