What they could be referring to is being able to buy the property all cash with the help of their HELOC. "Cash is King" as they say, so they may have been able to offer a seller immediate cash and get a discount on the property or purchase it off market at $50k under market/projected value, allowing them to also save money on the interest that would have been paid on that additional $50k had they not used all cash.
However, after reading that article, it seems as if they would not have been able to purchase all cash due to them not making a lot of money.
It's a confusing article to say the least. In essence, I do not think they actually saved money, I think they were able to make more money than if they hadn't purchased the properties, effectively countering the interest paid on the mortgage. Also, a lot of HELOCs have I/O options during the draw period, so that's how they could have "saved" money
HELOCs are more expensive, but they allow a borrower to leverage money they might otherwise not have. So, if it missing out on a deal because you don't have $50k of additional funds, then a lot of investors see it as worthwhile to purchase homes with this increased interest rates.
I apologize if this was not clear.
