Insync was never part of the original idea but is a brilliant way to track spending frictionlessly. It also removes the need for website integrations (like WooCommerce etc) because it takes place one step further back, at the level of bank transfers not the e-commerce platform.
If I've understood Insync correctly, it requires a customer to integrate a bank account in order to access loyalty rewards. That is, in my opinion, a huge amount of friction.
It's a one-off event that takes a few minutes at most. The process - and the protections around it - are similar to those for accounting software like QuickBooks, investment apps, online banking apps, etc.
https://www.incent.com/why-you-can-be-confident-sharing-your-banking-information-with-incent/After that, it completely eliminates friction. Retailers don't have to swipe a card at the checkout, customers don't even need to know that store offers rewards. It is dramatically better than the current system, which requires consumers carry multiple cards.
You are asking people to give you details of their every transaction. Under the terms and conditions of your program, do you then own the details of their spending? Is it part of your business plan to sell that data? If not, why are you collecting it, and if so, are you being transparent about this?
Further, am I correct that you are funding all loyalty payments to users yourself at this time? How do you plan to make any money from this activity?
It's a two-strand piece. Half the rewards come from customer subscriptions. Half will come from retailers who are willing to pay for repeat custom and the insights it gives them. And yes, customers can choose what accounts are linked and what data is collected. This is the age of GDPR, after all.