@Brett Wagner I am not sure I understand your question. Because you refer to people: who are not able to get conventional loans, not wanting to be full time rei and brrr vs buy & hold.
From my what I understand Buy Renovate Refinance Repeat is performed to allow you to keep acquiring unlimited number of properties virtually with your one initial investment. This is essentially a buy and hold system that allows you to recycle your money. Most people put down 20% down (or any amount) using conventional financing, cash or any other financing method on a fixer upper at a discounted price. Once repairs are done you pull your money (w/wo additional equity) through refinancing or HeLoC and move to the next property.
You can choose to do this either full or part time, stop anytime you want, refinance the maximum or lesser amount. Whichever you feel more comfortable with. I hope this helped but if you have more questions feel free to ask.