I believe there is, expecially if you want to make it an IP down track.
My understanding is that if you want to turn your PPOR into an IP down the track you cannot redraw the excess funds to use to buy a new PPOR and then claim the interest against the old PPOR(now an IP) as it was directed to a non deductable asset.
I believe if you put in an offset account you can use for non deductable asset and the amount owing on the original PPOR(now an IP) is deductable as you have not redrawn it, but you had the same interest saving effect as paying mortgage in advance while it was your PPOR(assuming 100% offset)
Hope this makes sense, this is what i was told by my accountant, obviously check with yours, usual disclaimers apply.