They can probably liquidate the drugs due to contacts they've made in that world faster, so even if the car was worth more it could be harder to liquidate. Stealing a car is worthless if you can't sell it or get a premium for it.

100+ pounds is a lot of drugs! And it's a gift that keeps on giving. Once you have the car codes, you can use the same vehicle many times.

Stolen cars are incredibly hard to sell. There is a reason criminals just steal one and ditch it later.

Easier and more money by breaking them down for parts. Strip it and abandon it.

Not in Juarez. That's where most stolen cars in the southwest go to die--in chop shops.

It's not just the vehicle, they also got the use of the driver as a patsy.

In addition to being hard to sell, this also multiplies the risk involved, which I imagine most drug runners would prefer to minimize.