Если коротко:
Standalone CA
This type of CA can't utilize features provided by Enterprise CAs. That is:
No certificate templates
this means that every request must be manually prepared and must include all required information to be included in the certificate. Depending on certificate template settings, Enterprise CA may require only key information, the rest info will be automatically retrieved by CA. Standalone CA won't do that, because it lacks information source. The request must be literally complete.
manual certificate request approval
Since Standalone CA do not use certificate templates, every request must be manually verified by a CA manager to ensure that request does not contain dangerous information.
no autoenrollment, no key archival
Since Standalone CA do not require Active Directory, these features are disabled for this type of CAs.