A plug-in version of a product is destined to be used only in places where there are sockets, which creates limitations and cannot be moved in large areas.
The charging board itself carries a power supply, and the power supply provides power for the product, so the charging version is less affected by the environment. Like a charging lamp. The charging version of the same product must be more expensive than the plug-in version, because the battery carried by the charging version itself increases the cost of research and development, and has to increase the price to make up for the difference
There is no difference in nature, it is electricity, ground line, live line and zero line connected.
The difference is: the charging curling iron is able to make the hair is straight into curls, which is called perm. To plug in is to link something for example: my phone is hungry so I can charge it. There is no WiFi in my home. I will worry why there is no Internet. Personal opinion If there is a good answer I will absorb good nutrition.
There is no difference in the use of hair, if there is a difference, it is in the inconvenient problem, charging is more convenient than plugging, plugging with the line is not convenient to use, followed by the price, charging is more expensive