Side note - typically, domain\servername$ accounts are used by the Network Service builtin account. So if any service is configured to use Network Service as its account and it requires access to an SQL Server, it will use the machine credentials (i.e. domain\servername$).

Be warned - ANY service that uses Network Service as its account will have access to any server/database that the machine account is granted access to, whether it needs it or not. Strengthening the position of 'use dedicated service accounts'.