Hedging foreign equity: why not?

Since VT (or VWRL) is highly promoted here on this forum. What does this mean for investors who invest in these funds? These funds include multiple underlying currencies but if one were to hedge some of them, then it would become quite complicated excercise.

I find it a bit difficult to accept that one would like to get diversification from international equities (because it is not so easy to guess which markets might perform) but at the same time somehow is pretty sure to be able to guess which way the currency pair might move.

For me it is simply not possible. And to be honest, few years back, JPY was safe haven currency too.