the legality would depend on code and regardless of voltage we do have 60 htz not 50 htz. That would only matter if there was a clock in the device. You also need to make the wire in the wall can handle it. Fun fact a lot of cheap device with times use the electrical frequency to keep time. That could also lead to wearing down of some parts faster.

Nope, it generally is not a good idea to try that. It might possibly work, but European power typically runs at 50hz (50 cycles per second) and the US is designed at 60hz. This small difference can mean that a European device would operate more quickly than designed. This is especially an issue with devices that have internal timers or motors.

Also, we have different plugs in the US for our 240v appliances, which would mean an interesting plug adapter situation.

So it could possibly work, or it could break the thing, or start a fire. Generally not for the faint of heart and definitely should consult an electrician.

It’s perfectly legal to install a 240v outlet. They’re most common for electric stoves and dryers, but you also see them for machine equipment in a garage or workshop, air conditioners, electric heaters. There’s no reason you couldn’t have one in a kitchen.

Finding an appliance to use it might be different. Not only would an appliance for another place be designed for different electrical system (eg 50Hz instead of 60 Hz) but there would be none of the typical certifications and it would have a different plug. Technically there’s nothing stopping you, but you’re probably past the threshold of plausible deniability.

That being said, it was tempting!