Uh, are you saying 70 + 90 + 110 + 130 + 150 = 550 free gold is worthless?
This rune is super, super good. High-risk, high-reward; you need to get the stacks early to make them worth it, and make sure you can really press the advantage it gives you.
But if you do, you get to play with two free kills of extra gold.
Every single Electrocute/Dark Harvest/Predator jungler or midlaner will take this in 9/10 games.
Also keep in mind that, unless you're really bad at the game, gold is worth more than its "gold in stats," since all completed items are over 100% gold efficient.