I find this quite hypocritical and possibky unethical in some respects. GetUp actively persued the banks in relation to their behaviour in the Royal Commission, including things like fees for no service and trailing commissions. To me paying hidden kickbacks/commissions (amounting to $120/tonne of abatement) potentially is no better than what the banks have done.
GetUp have used this and other (including referrals to a bank if the news reports are correct) customer subscriptions/hidden payments to fund their efforts. Yes, they do need funds for their campaigns but hidden commissions/subscription kickbacks is one of the reasons why I stopped supporting GetUp as they are not as transparent as those they chose to criticise.
If they fully disclosed that the kickbacks/(trailing?) commissions were for each customer, what it costs the customer indirectly and what GetUp receives financially, one would be able to make an informed decision whether to support their causes.