I guess the idea is to use the equity from one property to purchase the second property, and so on.

If there is equity can you use that to reinvest and come out better ahead doing something else?

This allows me to tune pricing after spotting trends. 

Anyone investors have any suggestions on the systems they use.

Just wanted to add some caution there because there’s this narrative by the S8 gurus out there that, “these people will live ANYWHERE!

I've walked through a property with a wholesaler and when I walked in I told him the ceiling height here is a big factor for resale and I can't use the comps he sent me.

Use the HELOC on cash-generating opportunities like flips, then use the cash generated to buy long-term buy and hold investments. 

Why does this make sense for investors?

Looking to have access to more capital to help do more deals this year and want to make sure i'm not breaking any laws and get into trouble.  

You can't actually pay it off directly because they've been securitized, and the people who invested in those securities did so because of the specific certainty of the payment schedule.What you do in a defeasance is use the proceeds of the sale or the funds from your new lender to purchase treasury bonds that are packaged to make the exact payment amounts and timings on the remaining term of the loan, and then assign those bonds to your old lender.