I don't think Nitrokey is claiming that the lack of USB Type-C connector is a good thing. Rather, it appears to be a specific reference to Yubikey's (and maybe also other competitors') "half USB" designs where the very slim HSM slides into a USB port, but isn't actually a USB-compliant connector.
I think both approaches are fine, and it's really a matter of preference. But it _would_ be nice if manufacturers of USB-connected devices that strictly speaking aren't actually USB-compliant would be a little more explicit about that detail.
Take a look at https://www.yubico.com/product/yubikey-5-nano for an example.
I think both approaches are fine, and it's really a matter of preference. But it _would_ be nice if manufacturers of USB-connected devices that strictly speaking aren't actually USB-compliant would be a little more explicit about that detail.