That makes buying much more risk-free. I haven't paid for return shipping on an Amazon purchase for years.
I don't know that I return enough to compensate for the ~$120 annual cost (I guess it's going up to $140?), but it does get me faster (and more to the point, deterministic) shipping as well, _and_ the other benefits like Prime Video.
Overall I find it still makes sense. But you do you.
BTW, your partner can probably share the Prime shipping benefit with you, if they aren't already sharing it with someone else, and if you live together. My wife can buy things on Prime with our one subscription.
[1] https://www.amazon.com/gp/help/customer/display.html%3FnodeI...