Probably in Australia and New Zealand. If you only plan to fish lakes, with no scrub and bush on sides, then the lighter options would work fine. But don't try this on rivers in Australia or New Zealand.
The black berries and scrub in Oz, or the just as horrible spiky (gorse?) bushes and scrub in NZ, will rip light gear to shreds in seconds (including U/light nylon tops and pertex windshirts!). If the weather is such that waders are needed in these countries, you would be advised to use durable (and, unfortunately, heavy) multi layer (5-7) goretex or equivalent waders, or you'll be very disappointed very quickly.
The only time I could see that you could get away with less in these countries would be fishing lakes and staying on water's edge. If fishing the open streams in Alpine country, you don't need to be wading, so don't waders in the first place.
BTW, this is why I still use a packlite goretex jacket (shock) at 450g (17oz), because I can still stalk in the gorse and scrub on the river side and not end up wearing tatters.