Morning,
Just think multilayered security.
You want to stop the scrotes from taking it for a joy ride. Normally a simple alarm and good quality lock will do this. If not then it is going to be smashed up and burnt.
You can also fit a cutoff switch , that uses a few dash switches set a certain way to allow the vehicle to start.
The "breakers" taking it for stripping. Locks and alarms will help them move onto an easier target. A tracker may very well help you get it back if they park it up for a few days to check if it is being tracked, as @ Marmaduke found. But some are using tracker blockers. Also something like "smart water" as well asa deterrent will help if the police come across the vehicle with changed ID or as stripped parts.
Professionals taking it for sale abroad. Chances are these are the boyos going for the good stuff, if they take yours then chances are you have lost it.
But also think about it, if you have disklock, pedal lock, Gearstick lock, alarm, cut out switches, .....are you going to use them all , all of the time? A Mulitlayered approach allows you to tailor the level to the perceived risk.
Ask the question: What works for you the way you want to live with it?
Cheers