We use Business Services to group servers together for CR notifications;

Defining CI Relationships - ServiceNow Wiki

We use Business Services as the top tier for all Applications with relationships flowing down to software, servers, Netgear and some other CIs. They are also handy to group up CIs by type, running services (i.e. SQL, IIS) and Tech. I think Business Services are one of the best components in Service-Now and are a foundation for all processes.

As to application team validation, I don't see that as anything more than a change task that requires completion.