What kind of risk is there to having the private key to localhost.company.com?
Other than that, obvious attack is to extract private key from your application, launch fake server and forge DNS responses for some poor guy (for example if he's using some untrusted WiFi). So his requests would be redirected into that fake server instead of localhost application.
Who uses these tokens, and what for?
As to certificates, they are required for some internet services. There's portal http://egov.kz/cms/en which provides almost all government services for citizens and to use it, you should own certificate (so you sign your request with digital signature and it's treated by law like you signed it with your hand).