Downside is you lose a fair amount of performance switching to 64 bit floats especially on low-end hardware
Think we'll run into a bit of a plateau eventually?
I mean, once we support 64 bit, in many domains we won't need to go much further, which means that hardware just needs to catch up. Of course, Moore's law is somewhat dead otherwise and Wirth's law is still very much alive, so that's a bit worrying, but I can feasibly imagine eventually getting to a point where 64 bit makes sense in most cases (maybe even embedded in a few decades, who knows) and that's that.