I'm looking to buy a new jacket for hiking/traveling during winter in Australia for temps between 8c to 15c and possibly in windy and rainy conditions.
I noticed that snow jackets tend to be cheaper than soft shell jackets and that they are waterproof and wind resistant, so I was wondering what issues I would face if I use a snow jacket?
I'd like to challenge a premise of your question:
I noticed that snow jackets tend to be cheaper than soft shell jackets and that they are waterproof and wind resistant, so I was wondering what issues I would face if I use a snow jacket?
You are putting too much emphasis on labels: "Snow jacket" is an arbitrary label that a company (seller or producer) may use, but it is essentially irrelevant to you. On the other hand "soft shell jacket" is a reference to a class of material used to make a jacket, so that's somewhat relevant. It's wrong to believe that's a uniform class of jackets, as in your case an "expensive" one. There's really cheap and crazy expensive soft-shells.
What you should put emphasis on is characteristics: Is a jacket water-proof, how breathable is it (this is not a binary condition!), how much (if any) insulation does it have, ... How exactly this influences they choice of jacket depends both on the target conditions and personal preference.
For your conditions and my preference (items of clothing that can be used as versatile as possible, and are dependable, enduring and reasonably priced), I'd go for a non-insulated, water-proof jacket. That is usually labelled "hard-shell", but I wouldn't be surprised if you found something with only very light insulation termed a "snow jacket". This won't be very breathable, but who cares in rain, and outside of rain you can open it or take it off -> very breathable. And for >8degC any kind of insulation below the jacket that you probably already have (pullovers or whatever) is fine.
TLDR:
Ignore labels like "snow-jackets", look for characteristics.
That said many so-called "snow-jackets" will not be water-proof and have too much insulation for your use-case, but there might just be one that fits it perfectly.
It would probably work and some of it will just depend on your preferences. Possible issues may include,
Like I said a lot of that will depend on you and how much of a jacket you need to feel comfortable.
Snow jackets come in a lot of different variations.
Insulation - from shell to full down insulation
Water Resistance - From light to full
Breath-ability - From light to full
Note that waterproofness is not guaranteed in a snow jacket. They are predominantly designed to be worn in snow not rain and despite the fact they are both water, snow penetrates a whole lot less than rain.
With the high chance of rain in Aussie snowfields I always go for outerwear with a high water proof and breath-ability rating, which of course costs more.
I use a North Face snow shell as an everyday (rainy day) jacket. Predominantly because it is my back up snow jacket, which is it's primary use. I also use additional layers as required.
As noted in the other answer, it is bulkier and heavier than a purpose built hiking shell, which could be an issue depending on the hiking you plan on doing. They also tend to not compact well. Day trips around the Blue Mountains, it would be fine. Long multi day treks..... nope I'd be going light and compact.
A little supplemental reading from a fairly big Aussie outdoor retailer: https://www.paddypallin.com.au/blog/choosing-a-waterproof-jacket/
I have been using a ski jacket for mild winter weather use this last winter. Our temperatures are not much lower than yours.
I was comfy when not very active, during cycling (in which most of the build up heat is in my legs, not my upper body) and when out in the wind while moderately active (walking briskly.)
But when doing very active things I often had to open the zipper a bit as the heat was building up too much.
While not completely waterproof, it was good enough to keep me dry for at least my usual commute of 30 minutes, likely would have kept me comfy for much longer but I never needed if to hold water out for longer.
From that I conclude that it depends one what you want the jacket for, if like me for the bright colour on relaxed bike rides, buy it. But if you want it for running in day time, it will be too insulating and therefor getting you hot.
Usually the last thing you want for snow is a waterproof jacket. Many waterproof breathable layers will ice up inside because at low temperatures water doesn't have a high enough vapour pressure to get through the fabric fast enough. I have a non-waterproof nylon shell that I use for winter
In general I find that wind is a much bigger determinate of my (dis)comfort than temperature. A good windparka that comes below my butt, has a hood and this and that to control the access the wind has to me can be worn over a wide range of temperatures. Adding a fleece layer and a toque under it, drops the range both upper and lower by 10-15 degrees C.
I own a fleece lined nylon jacket. I almost never wear it. Too warm. I think I keep it in the pickup for times when I didn't wear a jacket but wished I had.
