To powerful, to fast. I think the main reason is that a lightning strike is a few billion volts and only last for a fraction second, id like to see someone try to harnass the sort of power without blowing the absolute crap out of something.
res10. benjamin franklin did with a key at the end of the kite he flew but lightening dosent last long enougth be be really usefull and it is in the millions of volts and lots of amps
unlike benjamin franklin who flew a kite with a key in it to attract lightning which traveled down the line or thin wire, he had attached to the key, to be of any real use the lightening would have to be a continiuos bolt to be of any use and it would have to strike one place all the time not just here and there and we would need a continious lightening storm and lightning bolt to the one spot then they maybe able to use it by stepping it down to a useable level with a giant huge electronics lab transformer then we would need to turn it to dc then do what we need to or just reduce it to the ac level we need in all our houses