It's like herd immunity: if most phones have an activation lock, then thieves are less incentivized to steal them. Obviously they can still sell them for parts, but they're worth less.

> The temptation of a smartphone for a thief is dropping, thanks to Apple’s decision to implement a remote kill switch via Find My Phone that can erase and disable a phone once it’s been stolen or gone missing. A new report from Reuters found that iPhone theft dropped by 50 percent in London, 40 percent in San Francisco and 25 percent in New York.

https://techcrunch.com/2015/02/11/apples-activation-lock-lea...

In theory it's not needed since you could report your phone's IMEI as stolen and the phone would be block, for some reason it's not common among operators

https://www.gsma.com/services/gsma-imei/imei-blacklisting/

An iPhone can still be used without cellular data as a "premium" iPod touch, plus blacklists aren't worldwide and phones can be sold in foreign countries (a worldwide blacklist can be problematic due to standards of proof for theft and corruption being different - do you really want a third-world country to be able to dictate which phones can and can't be used worldwide?).

In my neighborhood recently, a woman was held at gunpoint and made to disable the activation lock. Thieves are getting smarter.

For straight theft, usually not, but in my experience losing a phone is a more common scenario, and quite often when tracking one (as I often end up doing for friends, since findmyiphone somehow counts as "hacking" to them) you'll see it taken all across town, the finder trying to figure out how to get it operational, then eventually giving up and settling on your offer of a finder's fee.

So the not-exactly-honest but also not actively a thief regular member of the public likely to find your phone is almost always swayed, I find.