BRRRR method initial cash

[Mack Braun]

Hello all. I am new to the real estate investing world, and I have a question on the BRRRR method. I am reading David Green's book on the matter, and he suggests that when using the BRRRR method you should save up or find another way to buy the house with cash up front. This way, you can refinance after adding value to the house and regain your capital. I am wondering what is stopping you from obtaining a loan to buy the house initially and then in a similar manner refinancing after the value is increased to again pull out your capital. I am confused as to why the second method isn't valid. I really appreciate all of the help in advanced. Thanks!