I'm interested to see how this develops. I've been pitched this idea multiple times over the years and been skeptical about how products would get either a) accurate estimates or b) sufficient participation. Leaving aside b) for the smart people working on this product, leveraging the Plaid connection + industry-level estimates of emissions per $ is the best proxy for a) I've seen so far.
However, the estimates still feel loose though, e.g. I change the subcategory of a purchase and the amount of carbon changes a lot. On the other hand, no one really thinks Fitbit steps are accurate as a discrete measure, and perhaps that's not really the point – it's the long term trends that matter here rather than unit-level accuracy.
Overall I'm hopeful and excited to see how Joro evolves. In our household we have a goal to reduce our footprint, especially around online ordering and grocery shopping, so I'll be interested to track how we progress on that.