It's true that the 6,000 banks in Europe have different standards, but the fact that the APIs exist and work and that the regulator is enforcing the use of real APIs (as opposed to screen scraping) is worth the effort to integrate each of the banks.
I work at Nordigen and we integrated with 1,500+ banks in less than 8 months. Some APIs took hours to integrate, some took a few weeks, but the fact that it was possible at all is IMO gamechanging.