Seems (if you can tolerate clickandbuy) no 3D Secure is needed

[Alhanelem]

I was able to register a non 3D-secure card without a hitch. If you don't have some kind of hate for click and buy but you couldn't use your card with SE before, you can use it now (Assuming the institution for your account allows the payments to them).

That is all.

Edit: According to SE, the 3.9% thing is not true, and no fee will be incurred through payments to SE handled by C&B.