I looked at CRW about two months ago after reading that Roger Montgomery’s team had invested in it. I decided to sign up as a CRW customer to inform my investment decision and my view is that while the user experience isn’t bad, it’s also not especially compelling. The main downside is that rewards you earn take about 3months on average to be released as retailers need a lag to make sure you don’t cash out a reward and then immediately seek to have the purchase refunded.

Given most of the referrals are for standard retail products (lots of fashion, beauty etc.), most of your transactions are likely to be at most a few hundred dollars or less. Most kickbacks are also only few percent, so your reward will usually most be a handful of dollars.

I have currently earned $57 in rewards comprising a $20 signup bonus (so one-time only) and $37 rewards from having spent $200 at Dan Murphys, $30 at Pizza Hut and $100 at Best & Less...I'm still about a month away from any of that making it to my bank account though.

Assuming I do eventually get it, that's $60 I wouldn't otherwise have so I do see CashRewards' value proposition for customers; and two of those transactions I probably only made because CashRewards sent me an email about a special offer that day, so I also see the value proposition for businesses in delivering new sales. 
But that said, waiting 3months to cash out $60 is not an exciting prospect, so while I think it’s an ok platform I don’t see it becoming wildly popular. In fact I think they will see high churn with lots of signups but a high rate of disengaged users gradually not bothering to use the platform.

Another concern is that there is an almost identical business also operating in Australia called ShopBack. A bit of googling for comparisons of the two businesses suggests ShopBack maybe offers slightly better reward percentages for customers on averge, though it depends what you buy. Irrespective of which business is marginally better, the barrier to entry is clearly quite low. 

So it's an ok-but-not-great experience AND it's already facing competition. For those reasons I chose not to invest, though I will likely remain a customer and continue to periodically check for discounts on things I plan to buy anyway.