To put it briefly, effective altruism rests on two philosophical ideas: altruism and utilitarianism.

In my opinion, even if you're not an altruist, you might still want to use statistics to learn about charity.

Some people believe that they have an ethical obligation to cause a net 0 suffering. Others might believe they have an ethical obligation to cause only an average amount of suffering. In these causes, in order to reduce suffering to an acceptable level, efficient charity might be for you.

It's possible that in your life you will not come across enough ponds with drowning people that only you can save and you will have to pursue other means of reducing suffering. An alternate method is charity, and statistics can identify which charities and how much to donate.

In order to save money to satisfy your own preferences, you might want to donate as little as possible. You might also calculate that a different time might be best to donate (like after you die). But if you come to either of these conclusions, you're still using the idea of efficient charity.