I can check out faster by rarely having to queue for the register, and I can scan things faster than a tired bored retail worker and know it's accurate. Self-checkout is also much less likely for me to catch a cold/flu/etc. as I'm neither in close proximity to the employee who was in close proximity to every other customer that week, and is touching every one of my items after touching every other customers' items. And, I can bag the goods the way I want them bagged, either for easier carrying, cold items together, or for how I want it organized to un-bag at home.

So, I consider self-checkout a real plus, not them stealing my labor. The exception is when the system is ill-designed or ill-tuned, so it halts and I'm effectively debugging it for them, except nothing is fixed b/c the employee just logs in and waves it through. With that exception, I still much prefer self-checkout.