Yeah you're right. It's a waste of time for those who have 40hr a week jobs. It would be great for them to implement something like this: You have a special vendor who sells them at the cost of 25 motes of light/strange coins/5000 glimmer etc. But you're only allowed to buy 3 a week per character. So if you have 3 characters, like myself, you have 9 keys at your disposal. Do what you please with em but you're not allowed any more unless you loot em from the chest and wait till reset.