Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - General We have 1.5Mio, How to make a better stronghold?

It's completely dependant on the story and narration, honestly. You may need or it may make sense to own a hideout, a house, a fort, a cave, a boat, or anything that could be considered a "home".
"home" or "headquarters" have been in game since.. forever, really. The new thing is being able to free-walk in it, look around, and to some extent interact with it.

In the Assassin's creed saga, the homestead is a rallying point, a resting place, and the headquarters from where you send people do tasks, manage trade routes, etc.
In Skyrim, it's a warehouse, holds a great RP meaning, and a resting place ( though you can rest anywhere really ).
In PoE, it is quite useless, true.
In DOS1, it was more of a thing tied to the story although it's true it wasn't that great.
In Divinity 2, it fit very well in the story and gave you lots of advantages for progressing through the game.

A home is the new incarnation of the "main hub". It's you default "go-to" location when you aren't sure what to do next or when you're thinking of ending your session. Arguably, it's the open-world / open-story equivalent of the headquarters from a thousand of other games, like Xcom or Darkest Dungeon. Arguably still, you will want to build your own house for obvious purposes in Minecraft, Terraria, Starbound, Don't Starve, etc. And while some MMOs feature housing, it's quite useless except to chill when you're a little bored, like in Wildstar, or a feature you can't ignore because it regroups a lot of services like your ship in The Old Republic. WoW recently put the Garnison system in the game, and while it's a bit too important ( most people spend most of their time in the garnison rather than with other people doing things ), they put a lot of very useful and interesting features in it.

So, do we need a home? Not necessarily. Is it stupid to put a home? The game story will answer that. Does it add nothing of value ? No, it actually does, as long as people behind it thought it well.
There are no clear yes or no, one thing is sure : if it is well done, as well as making sense in the context, it is a very nice and interesting feature to have in a game.