You are shoked that a half baked project with many wishful thinking and lots of unresolved or inconvenient properties has not been widely or even narrowly adopted?
They can not even exchange currencies. If you have to pay internationally, like on itch for example, and you have € and need to pay in $ you cannot do this with Taler.
And yeah, a problem is, that they call their stuff coins. That was a bad move. Because, as I just said, you do not exchange your prepaid wallet money into Taler Coins. Calling any concept therein coins taints the whole thing with cryptocurrency baggage and all possible early adopters that do not accept "coins" for various reasons will skip it out of principle. (And to make it even more complicated, they actually claim that you exchange your money to their so called coins. But this is not true, as you would have automatic currency exchange this way)
Even the developers freely admit that their project is not ready for real usage.
Imho, they tried to implement too many features. They even offer their wallet as a bitcoin wallet. Or having the wallet only reside on the device. That is a BS concept. I as a User would want something like paypal where I can send money at the ease of sending an email. That service would hold the microtransactions in escrow from both sides, till the escrow sums have accumulated to a big enough sum. The buyer would have to prepay. pp could have offered such a service, but they do not. They evolved into a mere buffer in front of credit card companies. Makes it a little bit easier to accept money, maybe a little bit easier to pay as well, but the fundamental prohibitivness against micro transactions does not change. (Oh, and while they are not cheap, they do offer currency exchange. Comparing prices with the one of your associated credit card is recommended.)