I was not familiar with the concept of open banking, so I just looked it up. Am I understanding correctly that it’s essentially banking with less privacy? Because the way I read it, who would ever want this?
Discussion
In general, people who haven't experienced any downsides of transparency when it comes to their financial holdings and activities, are likely going to trade their information for convenience and security. For this reason, it is hard to explain someone who hasn't felt any downsides of something, why they should limit themselves from enjoying more convenience.
This is why in the case of cryptocurrencies, as an example, the true benefits will only be felt when the downsides of traditional financial systems (and surveillance) reveal them.