It certainly depends on how much cleanup a given codebase really needs. But if your only other choices are reimplement everything in rust/java/whatever, never ever touch the core and stick to some FFI scripting layer and never hire anyone who doesn't have at least two decades of c++ on their resume, does carbon really look that unattractive?
What impressed me about carbon (apparently so much that I sound like a embarrassing fanboy even to myself, heh) is how determined they seem in trying to avoid scope creep: usually it's quite the opposite, every field of programming that's not entirely ruled out gets declared home turf that will eventually get revolutionized by the language (because a prototype exists and it looks pretty because it's still in that cute puppy stage when all the gnarly bits are conveniently left out)
What impressed me about carbon (apparently so much that I sound like a embarrassing fanboy even to myself, heh) is how determined they seem in trying to avoid scope creep: usually it's quite the opposite, every field of programming that's not entirely ruled out gets declared home turf that will eventually get revolutionized by the language (because a prototype exists and it looks pretty because it's still in that cute puppy stage when all the gnarly bits are conveniently left out)