I've noticed that my Facebook campaigns mostly get clicks from Android phones and have a very low conversion rate. I've set the campaign to all devices and automatic placements.
Answer by Jasper Kuria · Mar 08 at 12:03 AM
This is a well known issue for Facebook campaigns. You see, Android traffic is worth less because Android users spend less money. If you set your campaign to automatic bidding and a relatively low daily dollar amount ($20) or less, Facebook's algorithm seems to resort to showing your ad to more Android users so that you can get a lot of inexpensive clicks quickly. Once you have enough actions, the algorithm then optimizes and shows your ad to the users most likely to take your desired action (buy, opt-in or download).
To reduce this, you can exclude Android traffic in the device settings. This won't eliminate it all but you'll start to see more iOS traffic and fewer overall clicks.
According to this study done by Nanigans (the largest buyer of Facebook ads) based on 200 billion ads, iOS mobile traffic can be worth up to 1790% more than Android traffic.