When is it okay to use "kilo" in American English?

I was watching episodes of a documentary series called Drug Lords with one of the big video streaming providers.

Strangely for me, while the whole documentary was narrated with American accent and the overall focus was on the fight of the US government/DEA against drug trafficking, the narrator used kilo/kilos a lot during his voiceover when referring to quantities of the drugs in question.

That struck me as odd, given the customary use of ounces and pounds when describing weights in the US.

Is the use of kilo in the context of drug trafficking commonplace and therefore to be expected, or would this - from the point of view of a native speaker from the US - be considered odd in any way?

Essentially what I am interested to find out is whether there are specific areas aside from the typical scientific use of SI units where it's customary to use metric units or whether this was perhaps done in order to appeal to international audiences. After all even NASA and NASAs contractors have been known to use US units for scientific projects, so to me the use of kilo was unusual enough to ask here.

Kilo: is used as a unit of measure in international drugs traffic:

1870, shortening of kilogram. Slang shortening key (in drug trafficking) is attested from 1968.

(Etymonline)

Usage examples:

To produce a kilogram (2.2 pounds) of pure cocaine requires about a ton of fresh coca leaf, Wainwright told Business Insider. "It then gets dried out, it weighs a bit less, but that ton of leaf to start with costs only about $400 or $500 in Colombia," he said.

businessinsider.com

"A kilo of cocaine, current price around £50,000, if you double that kilo with benzocaine and you have two kilos the dealer could then probably knock that out for something in the region of £80,000 to £90,000. So as you can see the profit margin on their initial outlay is significant."

BBC.com