John Gruber, commenting on this BuzzFeed article, which makes the claim that Apple Card was created to lock you in to the Apple ecosystem:

I don’t think the reason for this is to keep you locked to your iPhone, although that’s certainly a side effect. I think this simply reflects Apple’s internal culture. Apple’s culture is to make native apps for everything as a first priority, with web interfaces as a much lower priority.

I agree. The Apple Card has the same impact on lock-in as Apple Watch. Neither is a requirement, and both have plenty of non-Apple counterparts you can move to if you want to leave Apple behind.

It’s the ecosystem itself that keeps you around, not any one piece of it.