As said once you manage to get inside one of these extra-territories you are technically on Spain teritory, but you have NO access (without a boat) to Spain (or the EU).
As an example, if you manage (from Morocco) to enter one of these you cannot be chased by the Morocco Police (that will stop at the border) and you can - say - ask/apply for asylum, but if this is denied the Spanish Police will bring you back to the border and put you in the hands of the Morocco border police.
And it is not like any "mainland" border that you can escape anywhere, these territories are tiny and you have no ways to go other than sea or Morocco.
Same goes for drugs, congratulations, you managed to bring some hashish in Melilla, if you manage to sell it there, good, otherwise you won't be able (easily) to bring it to Spain.
Most of the "drug activity" is on the beaches of Spain, around La Linea, Campo de Gibraltar and Algeciras:
https://estaticos-cdn.prensaiberica.es/epc/resourcescas/info...
speedboats leave the coasts of Morocco and quickly unload the drugs on the beaches, then they are loaded on cars and distributed in Spain.
The rest is attempts to smuggle drugs (and tobacco/cigarettes) hidden inside trucks or cars boarded onto regular ferries.
