Of course it matters. It matters whats the established patterns on the given platform are. None of these are universal laws but they are agreed upon standards that ensures that the user doesn't get confused. Thats the experience you should be aiming for anyway.
What should the radio button be then? Square?
These are not rules because they are the only way things can be done, they are rules because good design require consistency.
The user experience doesn't matter here, it's purely an aesthetic choice.
Of course it matters. It matters whats the established patterns on the given platform are. None of these are universal laws but they are agreed upon standards that ensures that the user doesn't get confused. Thats the experience you should be aiming for anyway.
What should the radio button be then? Square?
These are not rules because they are the only way things can be done, they are rules because good design require consistency.
The user experience doesn't matter here, it's purely an aesthetic choice.