Graces drinking up entropy and information because it helps maintain the engine they use to project themselves into the physical world

going to a restaurant and kinda absorbing the words off the menu

of course, anywhere with, say, modern wifi and mobile internet signals is saturated in graceavailable entrocalories, but it's like living on bread and water

on one hand, it doesn't necessarily make sense for her to destroy whatever she's eating. surely she can simply copy whatever information she's enjoying

but, on the other hand, the idea of "eating" a cheap paperback or something as a snack is very cute too me

the real answer is probably something like "you can find out more about a thing if you're willing to destroy it". For example, tearing a page out of a book gives you a bunch of information about the construction, material, technique, and age of the paper and stitches and glue and whatnot, and being willing to burn it does even more

a Grace can live fine without a good source of entropy, but don't be surprised if she's grumpy and can't maintain a good protection into meatspace

fires, conversation, and data-bearing electronics in particular help with this