Lighter and smaller devices can be made using electronic circuitry; reducing the voltage electronically is simpler and cheaper than increasing it. Small, inexpensive, travel adapters suitable for low-power devices such as electric shavers, but not, say, hairdryers, are available; travel adapters usually include plug-end adapters for the different standards used in different countries. A transformer would be used for higher power.
Lighter and smaller devices can be created through electronic circuitry; lowering the voltage electronically is easier and less expensive than raising it. Portable, affordable travel adapters suitable for low-power gadgets like electric shavers are available; these usually include plug-end adaptors for different international standards. A transformer would be used for higher power.