In what way do you think it is dangerous? Spoiler alert; it's not.
The main reason there are such power limits is because electrical devices are tested to withstand certain levels of interference from external sources.
Mobile phone vary their transmitting power depending on how close they are to the tower, so they do not jam other signals and it allows them to save power. Most of the time they are operating at a fraction of their peak power, where maximum power output is only used to ping towers when signal is lost.
The main reason there are such power limits is because electrical devices are tested to withstand certain levels of interference from external sources.
Mobile phone vary their transmitting power depending on how close they are to the tower, so they do not jam other signals and it allows them to save power. Most of the time they are operating at a fraction of their peak power, where maximum power output is only used to ping towers when signal is lost.