What do businesses do? Or what makes the businesses successful.
The ability to deliver a  quality product (goods / services) efficiently  and consistently. The reason why Walmart is such a phenomenal success as a business is because it can deliver a specific product efficiently, hence at a cheaper price, than any other competitor. Success in business means being efficient and have economies of scale. And I can speak some more here but lets desist the temptation:
Why did I start with the above because a business is a business so that it can deliver “” repeatedly. We have annual IT budgets that run into billions so that businesses can execute their function – deliver a specific product to their customers again and again. The importance of the word repeatedly and again is where I am going with the reason why businesses need business processes. Whether they execute in a person’s mind ( a SMB owner) or in a BPM system, there are business processes that repeat on a daily basis so that business can deliver the product or service custoemrs expect. Making these processes efficient and improve them rapidly is the goal of every CEO.

At the same time, there are professionals who have to deal with unique problems everyday – a doctor tending to a patient in ER, a lawyer dealing with a criminal case, a golf player on Pebble beach golf course with El Nino winds for a change…most of these examples are unique and being able to document each of these processes might :

1. Defeat the purpose (the patient might die) while the process is being documented.
2. Wont be cost effective – a doctor documenting the case (not patient history notes) and how he arrived at the differential diagnosis and then choose a specific antibiotic over another will not be cost effective as this decision making intellect has been honed over at least 10 years of med school and practice thereafter. It would be impractical to design for every permutation and combination.
3. It would not be repeated – I dont think the speed and direction of the wind at pebble beach is going to be the same again.
4. Each of these is unpredictable, you never know what to expect.

I think that the reality of businesses lies somewhere in the middle of these two. There may be certain processes which are so mundane that any investment would be a kill (and I wont give an example on purpose); there are certain processes critical and core strength of the organization, the procurement process for an automotive manufacturer, or order to cash come to mind immediately, which can benefit from a BPM approach. Even within these critical processes, 60-80 percent of instances follow a well defined path ,depending on maturity model of the organization, certain instances may need adaptive processes or segments thereof, or processlets as I would call them, and then again there are cases which happen in rare instances. 
As a CIO where should I put my money in – 
a) in those 60-80% process instances which can be automated, done faster better and cheaper; 
b) in those 20-15% instances where parts of the process are defined but not the whole process, 
c) or in those capabilities which are rare and in between – wherein even after the investment I might find that it was insufficient.
I think the choice is really between 1 and 2. But what if, <…pause>, there is a software that can do both. One that can execute my 60-80% process instances, support cheaper operational models for these, continuously measure performance of key tasks, improve  the process based on feed back ….
AND  with the turn of a switch, take those specific 20-15% instances and create an adaptive process model, modify them on the fly and execute segments of process as and when needed.
Time for my sales hat – please feel free to ignore
Fortunately, such a system exists and that is called Roubroo. It lets you model your business processes using BPMN 2.0 – executes them as per the semantics defined and alo lets you modify specific instances as and when needed. Please reach out to intro@roubroo.com for details.