You’re making assumptions that I’m thinking of Docker, which couldn’t be further from the case. I’m looking at using LXC/LXD to replace full-fat VM’s for highly stateful, single-instance services - game servers. Being able to live-migrate a LXC container to drain a host for maintenance is indeed a useful feature to have.
I usually assume all sorts of things[0]; I've become accustomed to living in a world where strict division between state and logic is assumed, even for relatively intensive stuff like trading platforms and very large ticketing systems.
Kubernetes has been more open to absorbing sticky, less-factored workloads than more opinionated platforms are. Red Hat have definitely made that point to folk whenever we and they are competing for business.
I had occasion to look at CRIU relatively closely in recent times. It is, as I said, early days, with annoying corner cases that need someone to patiently fix and polish (we ran into problems with networking, environment variables and process IDs).
In your case it will probably become attractive in the next year or two, because both Red Hat and Docker Inc (which is why I mentioned Docker) are touting checkpoint migration as a feature and I expect both will devote engineering effort to productionise it.
