I always need hugs.
My point is the object of the spin training is to prepare the instructor for the student who spins when trying a power-on stall. That training is better accomplished in a 172.
The Extra (I've only flown the 300) is funner than, well, almost anything, but that doesn't make it a better initial trainer. If the desire is for an aerobatic airplane then something like a decathlon would be a better bet, for basic and simple handling. Imagine spin training were compulsory for Private Pilot students (it should be!). As their instructor, do you think they benefit more from seeing it in the airplane they've been flying, or from a greatly higher performance airplane which handles totally differently?
Using an Extra is like teaching skid control to a Prius driver in a Corvette. Great fun, but it doesn't really translate and won't be all that useful when doing it for real.
It's obvious the decision was part of 'Shiney Flightline Syndrome' to attract students rather than for quality of training.