This is actually a pretty large debate currently. Some research suggests that a low CFU count with powerful strains is beneficial, whereas other research shows a high CFU count is better. 

We've opted for 10 billion CFU's so we could really focus on the quality and livelihood of those particular strains. In fact, Consumer Labs (very trusted source) recommends anywhere from 1-10 billion CFUs (see here: https://www.consumerlab.com/answers/how-many-cells-or-cfus-should-my-probiotic-have/probiotic-cells-CFU/)

Other supplement companies may include many more tens of billions of CFUs in order to "fluff" their product and claim it is superior.