In defense of Fidesmo, you can still get a developer account, you just have to e-mail them and explain your use case. Still, not as simple as previously where you could just sign up. They have also been very cooperative and helpful in their partnership with Vivokey, so I trust that they have good intentions, and I trust that they don’t intentionally mess up their own systems.
However, and that is the one of the reasons I conceived the flexSecure, I agree with @Devilclarke - I want control over the tech an keys I put in my body. As an open-source enthusiast and supporter of the hacker ethic, I believe in Kerckhoffs’s principle - that is your cryptographic systems security should only depend on knowledge of the secret key, and not any other arbitrary protections or obfuscations. Even disregarding malware supply chain attacks, I also worry about the potential of Fidesmo or even Vivokey going out of business in a decade? two decades? you never know. Call it paranoia, I call it independence.
I maintain a Repository of open-source applets for use with the flexSecure, (which are by the way the very same which are packaged for the Apex), because I believe everyone should be able to verify and modify software, especially the software they put into their bodies.
Fidesmo offers you a trade-off - enterprise trust vs. direct control. Even though it is unclear if the Apex will be able to eventually make payments in the future, the base functionality is there. The flexSecure will never be able to make payments (cryptocurrencies excluded), because no payment processor will allow their applets to run on an open platform, that is just how business works. In exchange, the flexSecure has more internal storage space - because the payment applet is missing. There might also be cases in the future where third parties (e.g. metro cards) will require a secure, trusted environment - i.e. the Apex. Fidesmos app-store also functions as a very user-friendly way of managing applets, without the risk and challenges of commandline tools and key management.
So in the end, it is about choice. Everyone is free to pick whichever product is right for them and their use case, the flexSecure happens to cover mine. I still work to push the ecosystem further on the Apex as well, because again, it’s all about choice.