North America, Central America, and a couple of South American countries standardized on 110-120 V systems. The reasoning was that this was less dangerous. At that time, most of these countries also standardized on 60Hz systems. Most of the rest of the world is on 220-240v systems, although some areas are 50 Hz and some are 60 Hz. This allow more power on the same wire. Most household wiring has insulation rated for 300V, so it can be used for 120 or 240. Japan is an oddity, as they use 100 volt systems.
In my previous job, I traveled to a lot of locations in the world. I did appreciate the electrical kettles running on 240. Water for my morning coffee boiled very quickly.
Given this, if I decide to upgrade from my present system, I will be going to a 240 volt system.