Setting aside whether you will actually miss your connection, Delta generally only provides hotels if the delayed flight is a result of maintenance, staffing or other controllables. If the first flight is delayed due to weather or air traffic control, you are unlikely to receive a hotel. Even if the delay is Delta's fault, there's no guarantee there will be space at Delta's contracted hotels. Sometimes they refuse to issue a voucher on the account of availability or give you a voucher to a hotel which does not actually have any space. In short, it's a crap shoot.