I suppose their is alot of irony in the passive investing /etf debate.
The main purpose of an etf is to be passive but more you look into it the more complicated it gets-further down the rabbit hole. Logarithmic nature of returns, volatility, do you use a derivative like futures,cfd's or options, do you borrow on margin or against your house or do you use a vanilla etf or a geared etf. What is the ideal position sizing? How much gearing? What is the opportunity cost of cash?How much cash do I hold? What is the tracking error. How much do I diversify? Do I hedge? What are the taxation benefits/costs.
It can do your head in. Not too mention that the whole basis or passive investing is the mantra that in the long term that asset prices will go up. This has not happened in every country around the world and therefore an assumption or in reality a bet on the future of Australia.
I remember years ago a finance lecturer when I was at uni said verbatim, I just buy the top 20-30 stocks and a few small caps here and there, then I look at it every 3-6 months and adjust the portfolio slightly. I can't justify the time, complexity and effort of the other options and also can't justify the fees.
and of course THIS IS NOT ADVICE
my two cents.