It is if your intention is to get rare item drops from the enemies
Only problem is that it's limited to what enemies your pawns can hold down for you. The really really great stuff is what you get off of the boss enemies, which you cannot hold down to steal from to the best of my knowledge.
I also found pawns that give Veterans Peripate (2x XP), Talgius Miracle ( Def boost whole party), & Jewel of Visstitude (Anodyne bubble on all allies in range)
The description of the skill is thag you can steal from held enemies and Blind or Sleep enemies. So any enemy that can be blinded or stolen from can be put to sleep. Master theif makes it better because you can steal 2 items and have a chance of getting the high end rare gear.
Cyclops for example give Cyclops Veils. High end head gear and they can easily be put to sleep or blinded.
I used sleep and blinder arrows to get Yellow Poison Safe from Sulfur Saurians to upgrade my rusted daggers. Live stock give healing items and backfat oil. This is in addition to what you get from killing them.
Just hire a mage with Blearing. If anything you can hire a bunch of Striders with Master Theif or make your main a Strider. Then play a Mystic Knight they get the sleep spell. --- Castlevania Lords Of Lycans And Trolls