The old TWA terminal was always a place apart from the other terminals. Most of the terminals at JFK are basically large boxes with airport gates on them and frankly they don’t even handle passenger flow very well. And the whole place looks rather ratty. I remember picking people up or dropping people off at that TWA terminal and it was always a great experience. The rest of the terminals, not so much.
I’m glad it’s being saved. On the other hand, airport terminal and tarmac space is valuable and giving it up for a hotel seems rather pointless.