As you can see in the photo below, a page may have certain groups of people who like it, but may be reaching a different set of people. Outside of advertising, this is important in general. If you start a marketing campaign targeting your local customers instead of your national ones, or men instead of women at Valentine’s Day, looking at who you are reaching will tell you if you’re succeeding in reaching the targets of the campaign. Outside of that, it also tells you general information about who tends to be most engaged in your business. This will be good information to know if you have trouble nailing down your perfect customer, since those who interact most with your posts are most likely to be in this category.
What differences do you see in Page Likes VS Page Reach?