Because you can disable debugging by setting the debug IO pins to GPIO there will be no access as lined out in your linked article.
When protected correctly there is no chance to get hands on your program. A reverse engeneering of the code will never get you to something usable as the source code is.
So you should care for your PC not getting hacked and the sources get stolen.
If you take the proper steps to set the unit to "Kill" mode, and the GPIO pins set to IO (NOT DEBUG), then anyone who attempts to get access to your flash code will either:
1) Burn the chip
2) Spend years to carefully pull apart the microscopic pieces, and most likely burn the chip anyways.
3) Try to mimic the functionality of your code, but without having the actual code, will only have a passable mimicry of what your code handles/does. This only after a long period of testing and poking at the chip as your code runs. (months/years)