It depends upon whether you like exploding concrete in the building, really.

You would prefer to direct the lightning to the outside of the building, not through the structure. Better to lose the conductor on the outside with possible charing to the exterior, than atomizing the conductors and causing structural support damage to the inside. Much easier to repair and paint over anyway. The wires are dedicated for arresting the strike and are usually covered over to look better and go directly to ground on the outside. The building, such as a huge skyscraper, should be able to dissipate the strike by its own structure alone. However the possibility of the charge not going directly to ground and entering the electrical system is always a possibility

Thank you very much. I agree with you. what you said means that it is not prefered but not forbiden to be used. could you provide me with any documents that forbid using them or a link that i can refer to.

thank in advance.

Here's one.

How do you know when the French army is preparing for war?

There's not a white bedsheet to be found in the entire country.