Everything wants to go higher for all manner of reasons, and the semiconductor switches probably don't care all that much. If the jump has to be made, make the jump as far as possible so that the jump doesn't have to be made again.
Is there a safety reason or something?
You lower the current by lowering the voltage.
I assume you meant increasing there.
When you're talking about safety though, the issue is what happens if the voltage gets applied to your body. In that case the relevant formula is I = V/R. R is the resistance of whatever circuit you've mistakenly formed through your body. The higher the voltage applied across that circuit, the higher the current that will flow. (This is also why it's more dangerous if you're wet, or in bare feet, for instance, because those things lower your resistance, resulting in greater current for a given voltage.)
So once the voltage is applied to your body, the higher it is, the more current flows through you
(Some assumptions about source of electricity made)
Current and Voltage are intimately related. 1V with a 1kA capable supply will not hurt you.
Safety is of course a huge component. 48V is about the limit before special isolation and insulation is required.
There actually is an existing sweet spot for 60V FETs, optimized for traditional 48v power systems. I've got to wonder if they're going to use -48v to allow simple driving of N FETs, or if the ubiquity of modern high-side drivers has made that a moot point.
Yes, actually they do. Power MOSFETs are usually in the 30-60V range. When you go higher than that, costs go way up and you generally need to switch to IGBTs. MOSFETs capable of switching 30V loads at extremely high loads (like 100A) are dirt cheap. Power devices capable of switching 100V are not.