The way this article is written leads me to believe the writer has not played the game for long enough to make a fair assessment on the gems currency.

I have been playing this game for roughly over a month, and put $10 into gems in the beginning. My roommate started a little over a month before me, and refuses to put money into the game.

The amount of time to invest into buildings/resources/farming scales up with how progressed your town is, and gems are present to alleviate this strain. The implication that gems are necessary to win are unfound.

The game follows a simple town building principle, use currencies (gold / elixir) to build/upgrade buildings, however you can only upgrade them to the limit your town hall level will allow. The way to gain currency is attack other towns (to steal their resources), or use gems. Even if you use gems to upgrade your things, you are simply progressing further in the game, at the risk of opening yourself up to more powerful enemies. When you attack weaker enemies, there are diminishing returns (look up the loot multiplier). So while gems allow you to progress, you must also adapt and attack higher level towns. These higher level towns can be achieved without any monetary investment in the game. Gems just allow you to reach that stage sooner.

I bought gems in the beginning, because the game uses a builder mechanic to limit how many buildings you can build/upgrade at one time. When you start out, you have 2 for free. You can have a maximum of 5, however these are bought with gems and the cost increases each time you buy one. With $10, I soon had 4 builders. With this, I was able to progress much faster than my roommate. I am catching up to his level quickly, almost at where he was in two months time with one month invested.

Additionally, gems can be attained for free by clearing brush, however it will be a nominal amount versus buying them outright. But to say gems are required to win this game is not true, but it does save you time versus waiting around a week for a building upgrade to finish. The main thing most people need to realize is this game isn't about spending money, but investing more time into it. The game is a continual uphill grind where the true currency is how much time you devote to it, but I'm still having fun with it for now.