I mean if law enforcement or other state actors are surveiling their comms, it makes sense to have it be anonymous, but I just saw a guy who was obviously a drug dealer in the underground with an iPhone in one hand and two Nokia feature phones rubber banded together back-to-back and thought that realistically the type of cell-tower triangulation and coordinate correlation that would need to be done to correlate his identity as The owner of both the iPhone and the work phones is already done completely automatically/preemptively/wholesale/dragnet-style. Snowden disclosed the NSA giving tips to local LEAs and the DEA while requiring them to conduct parallel reconstruction so as to protect the NSA's racket and also to avoid invalidation of evidence by fruit of the poisoned tree/Wong Sun (?) doctrine. Is there realistically any security advantage to maintaining dedicated devices for illegal business?
Sounds pretty sensible to me. There are clear security benefits as long as they correctly compartmentalize their usage.
I don't think that the NSA / GCHQ threat model applies to most dealers. Without any other other inidicators (terrorist email history / known to the authorities / saw them looking dodgy with 3 phones) then there are a huge amount of phones that are co-located legitimately for large portions of the day. Especially in a city with tower blocks, work/personal phones, different networks etc there is a huge noise to signal ratio.
A low/medium level dealer has a threat model of local law only. Compromise can happen via customer or supplier or possibly by observation on the street. Any of the candy bar phones can be disposed of at will. Rotating the number via copying numbers between phone and sim is pretty quick and simple. One phone for customers, another for suppliers and the iPhone for personal.
In case of customer compromise ditch that phone, supplier compromise ditch the other. Caught on the street, ditch both in different places. Keep the personal phone...absence of a phone just encourages the cops to look for the ditched ones and that phone is clean.
The obvious one is money. While the technology exists doesn’t mean the average cop has access to the data or the budgets to make use of it. Also then the ability to get a warrant to use it. Think of the drug dealer doing a multi layer of security around his identity - it’s one more ring.