Of course an ADS can be very effective. You're doing the same thing as an extender to some extent, although an extender routine is more involved & monitored (you keep pushing yourself during a routine, while with an ADS you cant do that unless you want to stick your hands in your pants in public)
An ADS is a good anti-turtle device though and can definitely help you maximize gains from a routine. Lets say you only had 30minutes a day for a quick stealth routine, then an ADS might help a lot.