I’ve unfortunately had the pleasure of needing one of these interlock devices installed on my car back in 2010. It’s definitely been awhile but the device only limits where you could go if you had alcohol in your system, and that limit would be NOWHERE. If you were sober you just had to blow clean every 5-20 minutes and I could drive as much as I pleased. The option without the device was no driving except to and from work and maybe the grocery store 1-2 times a week.
I’ve had one before and without it you can only go to work and the grocery store. With it you just have to blow sober and you are free to drive as you please, it’s like having the judge in the car to make sure you don’t fuck up.