I suppose you can use such certificate to MITM yourself to inspect the traffic to/from nodes you control, but pretty much every tool out there has features to generate certificates on the fly.
Any software or hardware that needs to intercept HTTPS.
One common example is antivirus software that block malicious content. It can install this wild-wildcard certificate, and act as a proxy to all sites the user visits. There are obvious security issues to it of course.