@kkarhan @F3715H @JuxGD
Thanks for the link.
Two observations:
I wouldn't call the optional (in the sense that an account owner doesn't need to cooperate) "viewkey" feature of Monero the "same" as the taxability guarantee in Taler, but it indeed would allow an honest merchant to disclose taxable income.
But according to https://www.getmonero.org/resources/moneropedia/viewkey.html, the data available for viewkey is not even reliable:
... However, outgoing transactions cannot be reliably viewed as of June 2017. Therefore, the balance of a Monero address as shown via a viewkey should not be relied upon.
Anyhow, as for comparison of #Taler and #Monero, I just say this: People (and societies) have options to choose¹) from for anonymous-for-buyers payments. With respect to taxability I'd argue that the regulatory compliance and guarantees are stronger it Taler, which - I think - is more preferable for society, but your mileage might vary.
¹) Of course, when and where the more challenged by regulatory #Taler becomes available.