Friends make your account look "real" to other facebook users. You can get away with doing group marketing and having less than a hundred friends.
Still, you should vary how many friends each of your accounts have. some should have less than 100, some should have more than 300.
Of course, if you plan on marketing to your friends on your account, be very picky with your friends. Random people don't buy products. Targeted people buy products. You could get 5000 in 2 months, and none of them will interact with your ads, or you could get 1000 targeted people in the same time, and 20% of them will interact with your ads.
0% of a shit ton is equal to zero.
20% of a little bit is a tiny bit. Which is a hell of a lot better than zero.
If you plan on marketing to your friends, research how to add people of a certain market or niche.