It should have NOT SECURE written in big red letters - everyone has your private key, so there is no security at all.
"sslip.io's primary purpose is to assist developers who need to test against valid SSL certs, not to safeguard content."
"Although there's no technical reason why you couldn't use the sslip.io SSL key and certificate for your commerce web, we strongly recommend against it: the key is publicly available; your traffic isn't secure."
This seems like a very silly service to operate, and as remarked by others, I guess the certificate will be revoked soon because the private key data is out there.
Mostly surprised that this wasn't obvious to a company like Pivotal from the first moment.