@Flamfag123 @goodhunter @mahtan
Yeah, could've used her to herd the ants back but anything else is probably useless.
Firstly, since she doesn't have a body, she can't make more ants and / or create ants the same as Beru anymore.
Same thing as it is irl. Dead Queen = Dead Colony.
Secondly, she will have a higher authority over the ants and may conflict with his decisions (they may be absolutely loyal but that doesn't mean that they'll follow exactly as he orders because there's a middleman)
And Third, I don't think she has any more unique ability, since she's a queen, and considering her size being too huge (will hinder mobility); inability to use ranged magic (other than command) and that she isn't as strong as Beru, it's only reasonable to let her go.
But I do indeed like the idea of collecting her just for display, but with a limited space, I'd rather find a more 'special' type of unit of another race (of monster of course) and be content with the best.