No, I meant an implant which is one piece, not two or three subassemblies. In your link, the implant has a titanium piece which is screwed into the jaw bone, and then a crown is attached on it. Two pieces.
Yes, I understand the reasons, but OTOH, any interface of two materials is prone to become a place for bacterial growth. That's why we still can't make fillings which never fall off.The reason for two pieces is to allow the bone to regenerate/consolidate around the implant to make it secure. If the crown is attached too soon, the implant wiggles around in the hole from the chewing forces, eroding and enlarging the hole until the implant falls out (or breaks the bone).