someone eli5 why is zarf becoming so popular?

My guess is because getting hacked in one way or another is getting more common so people are ending up with more security lockdowns at work and the easiest way to get around the lockdowns in most companies is an airgapped network.

RKE2 was built to US government standards. US Gov has a long standing history of air-gapped configurations. Moving the RKE2 and applications on top of it into an airgap is hard to do reliably. Defense Unicorns are the people behind Zarf and they are government focused so they are solving the government problem for government customers. There are a lot of government customers because RKE2 is the only k8s distro specifically tuned to government standards. All this results in noise around government solutions.