I am not an expert but according to Wikipedia BSCCO is not suitable for high magnetic field strengths. In the video - which I only skimmed - the main point seems to be that they can now build vastly smaller fusion reactors because now super conductors supporting higher fields strengths are available and the energy density of a fusion reactor scales with the fifth power of the magnetic field strength. They also specifically mention rare earths which does not match BSCCO which were, last but not least, also discovered in the late 1980s.