For me, the increased perf is nice, but what I really want is increased longevity. IME, microSD is a poor fit for hosting a R/W filesystem. Every time my Pi based systems have gone down, it's due to a faulty microSD. I was using well rated microSD cards and they still died relatively quickly(months, not years).

I suspect they'd be fine if I was running a read-only rootfs, but with a lot of the applications I run(i.e. HomeAssistant) you need R/W capability.