Sorry for skepticism, but I'd say it's certainly a better to invest the same money in making the same RPi (or alike device(s)) globally-addressable and accessible from the Internet.
That's a nice idea, but unless you control the network - and if you're deploying devices for other people, you probably don't - it's just not feasible. You'll have layers of NAT and firewalls preventing it.
That's a nice idea, but unless you control the network - and if you're deploying devices for other people, you probably don't - it's just not feasible. You'll have layers of NAT and firewalls preventing it.