Benefits are better PSU efficiency (~3%) and higher load on same wire size.
Someone told me it would not work (or break) because the 240v of Europe is not the same as 240v in America, his argument was about phases and how the 240 is made from the 3 wire.
Personally I would simply change the breakers, identify the outlets as 240v and take the risk.
What could go wrong ?
I would suggest you change the outlets to Schuko or, well, any that are used in 220-240V countries, then you will be less likely to plug a 120V device to 240V outlet.
Anyway, I read somewhere that 240V in US is made from two 120V live wires 180 degree out of phase. I do not know if that's true or not (I live in Europe so I have no way to check), but in Europe 230V (it can be 220-240 depending on the country) is single phase (meaning you get one live wire and one neutral). I also do not know what the effects of split phase 240V would be on the devices (maybe none).
Also, the frequency in Europe is 50Hz, so, for example, a synchronous motor will spin faster in the US.
Here in my town (Blumenau, in Brazil), our voltage is 220v, delivered just two wires (phase and neutral). But we have the option to request a tri-phase power (330V), making the energy more efficient (be my next upgrade).
