I would support Amazon doing this if they took anime seriously enough to do it properly. It's at least better than Animax.
However, £79 per year (plus a premium in the US) is hugely overpriced for what might be one show per season at best a person actually wants to see. All it does is make Crunchyroll seem even better value. I could afford it if I wanted, but I could just spend that £79 on something else - and that's what I'll be doing until they get their act together. If it had worked the way I thought the anime service in the US was going to work, I might seriously have subscribed.
What would be the absolute best for customers would be companies putting their shows on both services and letting the quality of the service compete for viewers, not locking things away as exclusives to benefit distributors and distributors alone.
R