Any negatives to buying on a credit line and then doing a re-fi?

[Paige Hutchinson]

I have come across 2 duplexes and a triplex that we are interested in.  I was thinking if we buy them on our credit line, then after 6-12 months (whatever the lender requires as ownership time), re-fi to remove from our credit line.  My thinking is we would be saving on closing costs because a re-fi is very cheap and of course so is a cash sale.  We won't have to put 25% down because the re-fi is based on 80% loan to value.  Is there anything I'm missing?  This looks like a win/win to me?