No Point In Lightning Strikes
The level 5 lighting spell deals 420 damage. I see you're concerned about cheap players using it to steal resources without skill, so let's examine the incentive to players to do this.
A level 11 Gold or Elixir Storage has 2016 HP. Four, level-5 lightning spells will deal 1680 damage, not enough to kill it. Now, that cost the player (who is TH9 because he has 4 spells) 88,000. How much gold did that gain? The player has Town Hall 9 if using 4 spells, so...
...against TH7, there is a 50% penalty. 99,000 gold is available per storage (2 at TH7, level 10) but the penalty makes that 49,500 gold. So spending 88,000 to do this would be foolish.
...against TH8, there is a 10% penalty so 89,100 gold is available. BUT THIS WON'T KILL THE STORAGE COMPLETELY. In fact, 1680/2016 = 83% (roughly). 74,250 gold would be netted this way, so spending 88,000 isn't worth it here either. By the way that's assuming they have only two storages. Most TH8s have 3, so 59,400 would be gotten from the complete destruction of the storage, but only 49,500 might be achievable through lightning.
At this time, I should point out that the progression is NOT linear. That is, x% damage to the storage does NOT get you x% of the available loot. It's a sliding scale. The first few hits don't take much, the last few take a lot more. How did I learn this? When someone dropped three lightning spells on my Dark Elixir storage and only got a quarter of what was available.
So even against a fellow TH9, spending 88,000 gold would only get you 41,250 and only 10% more against TH10, IF IT WERE LINEAR, which it is NOT, because SuperCell is full of computer programmers who know this stuff. I'd have to guess it's some sort of compound interest curve.
I suppose you could find a TH10 and (assuming a linear relationship) Get your 108,900, but that only profits 20,900 gold, and shooting out a gold mine with 1 archer can get you that in 2 minutes instead of 2 hours. Should we get rid of archers then?
And let's examine the gem route. It costs 80 gems to prepare 4 lightning spells instantly. According to the wikia,
http://clashofclans.wikia.com/wiki/Gems, the highest amount of gold you can get from lightning, 49,500 (too high because non-linear), would cost 69 gems.
So gems or not, no matter what your TH, it's just not worth it to use lightning as a cheap way to gain gold. Maybe you can willingly trade gold for elixir or dark elixir, but it's easier to raid or cheaper to just buy it with gems.
What Lightning Is Actually For
1) Remove ONE critical target. At the TH8-9 level of play, many defenses--when raised to the appropriate level--can withstand three or even four lightning hits (Air Defenses take three, Inferno Tower 1 takes four, Inferno Tower 2 survives all 4 hits.) Maybe you can get two of three mortars but a TH9 would still have at least level 6 walls and FOUR Wizard Towers to deal with the bunched-up troops.
2) Mass Kill Clan Castle Troops. So, your 12-18 Giants are tearing up the defenses when all of a sudden, 15 barbarians just cut all the Giants down. Giants don't resist being attacked when there are defenses around, so they just helplessly deal less and less damage as a group until the pack, and your hopes, are dead. Unless of course you can drop lightning and kill them all at once.
3) Rare: Finish Off A Critical Target. So before you can deploy the Dragon that Air Defense HAS to go. Your archers have just about got it killed when CRUNCH! A Mortar shell lands and crushes 20 little tiny Archer heads. You can't deploy the rest of the ground troops, the cannons will get them and you'll have no one to pick up the loot before time runs out (Giants are sssslllloooooowwwww). So, ZAP! Finish it off with a lightning spell and unleash the beast.
So the Lightning spell is a valuable tool that can save your raids if you have the skill and timing to use it properly. And some people do occasionally hand you 20 trophies and drop 3 lightning spells on your gold storage. Those are new players who "just wanna see what would happen" and as soon as they see the math, they'll knock it off.