Is it Sustainable

To all the stories I've read it's either forgive and forget what Invaders do changelings are interesting species but never fully thought through thinking that keeping them fed or spreading them out will keep them happy but there's always issue of sustainability true you can get from all the chance all the abilities you desire but in the end they are not sustainable and species there are in essence the ticking time bomb. In other words a Bottomless Pits of hunger in essence would you invite parasites on to yourself just because they look cute or they're not a problem at the moment it's a simple question are they sustainable or not and all the stories you read or would you do would you handle it? Let let me know?