I would say so, yes, if you're indoors theres no reason that using devices could be any more dangerous.
If you're planning on using an old mobile phone with an ariel on the top of a hill in a thunderstorm then its probably not the best idea though.
I think a lot of these things stem from people using TV's in storms and lightening hitting the ariel and sending a huge charge straight to the TV. If you do use a TV ariel I would probably suggest avoid using your TV during lightening.
