Well, it depends, does it come with an adapter? If it does I don't see any reason to turn it off except if it's in the same room you are sleeping in.
And if it's batteries only it's still something cool to look at once in a while and show to friends.
That being said I just purchased a Malgus PF with a faulty lightsaber so ofc I won't be able to do that with it, but I'm still really glad it's got a lightsaber in his hand. A Sith without a lightsaber is strange for me, especially one with a suit as plain and seen as many times as Vader's. However I agree that it should come with a change of hand and a lightsaber hilt to add to the belt for people who aren't really feeling the plastic pole look, should be standard with all statues wielding a lightsaber.
Light ups are a nice feature, really adds something, if they can be added they should period. I have been collecting for more than 10 years but I'm not old school whatsoever, I have no problem saying a lot of old statues from other companies or old PF's look like crap compared to a lot of the current stuff, and light ups used to be awful in many cases. But now they are awesome.
The pose by itself doesn't make a statue, it's really important but it's not enough either. I wouldn't even display the Attakus if someone gave it to me, honestly. Doesn't even come close to this PF imo but then again, I have never liked any of their statues.
Anyway, you are really into blasters and Stormtroopers whereas I am really into Sith/Jedi, and lightsabers so it makes sense that we have different views on this