Yes, the higher you go in the frequency the more it is like light. But even at mm-wave such as say for example 28Ghz you still have penetration through walls, b

Yes, the higher you go in the frequency the more it is like light. But even at mm-wave such as say for example 28Ghz you still have penetration through walls, but the loss is very high, for 28Ghz it is about 19db for a according to IWPC for a typical house wood wall. For light, the loss is basically infinity. Building a user device, like a phone or tablet with stepper motors or servo mechanisms is probably not very realistic I don't think.