This is a nifty idea, and clearly inspired by the likes of
www.acorns.com in the US.
Its admirable to have these interventions to get people to start saving, but I would prefer if didn't automatically go into Tax Free savings bucket. Firstly, virgin savers will need to save a lot and earn a decent return before those returns would be taxable anyway (outside of a tax free wrapper), and that's because the first few thousands of investment return every year is tax free in your hands anyway.
Secondly, for people saving already, this is not the nicest vehicle to do you tax free savings in - even though its free. Personally I would want to put the tax-free maximum away with intent (if I could afford it) and know that box is ticked.
This app for me is clever because it gets people to save without it being noticeable. The fact that its tax-free, means that one needs to take notice of how much is going in, in the off chance you might breach the limits and face the hefty SARS penalties.
And finally, the cynic in me believe that "when a product is free, you are the product". Either Liberty is getting a wealth of fantastic data on you (and spending habits and data is very rich and powerful) or it might be a matter of time before a Liberty adviser starts calling.