RPA can be used where we have a define set of rules for processing that is the information is in digital format and structured data.
AI is used when the information is in an unstructured data where you can feed in series of decision making recorded by human to make future decision by the machine. Increasing the number of practice cases will make AI for a better decision.
Examples for RPA can be automatic payment chasers for pastdues of credit cards, Rule based transaction routing to various queues, Sorting of document and processing them on system which are rule based.
AI can be for unstructured data. e.g invoice information format will be vary from one customer to another however the type of data will be the same. We can feed in various types of invoices to be learnt by the machine to obtain common information ( Seller name, Buyer name, goods description and unit price), sorting of scanned customer document/Swift messages based on content of the data to various Queues if not to miscellaneous Queues.
Highest level of automation can be achieved without the two working in tandem will be based on the process whether it can be done through rule-based where AI will not be required and if the process has combination of both structured and unstructured data using AI and RPA will be a signification shift.