I think Butterfly's official explanation of the Tenergy range largely makes sense in light of the physical structure of the rubbers. But knowing these descriptions also colors my interpretation of the way the rubbers play. I've used all four Tenergies (05, 25, 64, and 80), and I'm not sure that I would have come to the same speed/spin conclusions as Butterfly had I not known the marketing in advance.
Based on how the rubbers feel, I would group 05 and 64 together as having a similar "feel" in terms of gripping the ball and sponge engagement. I would put 80 and 25 in separate categories. They both feel different to each other and different to the other two Tenergies. 80 has a much more muted "feel" compared to 05 and 64, which both give satisfying feedback (one reason I think they're so widely used). After using 80 for a while, even though my shots were no worse, I found that the rubber just didn't give me good feel/feedback, so I swapped for something with similar playing characteristics but which feels better to me.
Regarding the speed of T80 and T64 - the term "speed" doesn't really make sense to me when comparing the tenergy range, since they all have multiple gears. I think T64 is an excellent rubber in terms of control, being less reactive to incoming spin than 80 or 05, and thus better for blocking and flat hitting. It also gives nice short game feel and isn't too bouncy. And it transitions well from hitting into fast, close to the table looping exchanges. The one area that I found slightly more difficult with T64 was opening loops against backspin, but my technique was also poorer at the time which might account for that difficulty. The only other issue with T64 is that the ball can sometimes slip across the topsheet if you don't get enough sponge engagement.
So in conclusion, I would prefer T64 over T80 as a backhand rubber. Although T80 is also a good backhand rubber, it feels more to me like a muted T05, and the weird feel (especially on short game) eventually got to me. T64 feels more unique, keeping the monster spin capabilities of the Tenergy line but also having some more linear gears.
The caveat is that all of this testing was done with the old celluloid ball. I'm currently using Rakza X on backhand (on HLV), which I would highly recommend as a potential alternative to consider alongside the Tenergies.