@Senad Pali It's all relative...my personal opinion is that this technique is not sustainable...and you're killing your cash flow and equity by pulling it to roll into another property. So, keep repeating this process and have multiple properties with all debt and no cash flow...it's not a good ending.
Accelerated debt payoff makes more logical sense...I would be willing to wager that your one property paid off entirely will cash flow more than your next 4-properties you assign debt to...being successful as an investor has nothing to do with the number of units you own.
It's difficult when places like Bigger Pockets push the "BRRRR" technique to gain popularity points, but never cover the other side of the story. There is a balance somewhere, but sustainability is key.