YANBU, it would make me feel uncomfortable too. I always think it's weird when you see an otherwise calm, non-violent person hitting their children. Even though not everyone who smacks their child is automatically a thug, and people have allsorts of reasons (or excuses) for doing it, it always seems cowardly to me. I just think, well you wouldn't turn around and slap me if I'd done something similar, so why a small child?
I was smacked - not beaten, and I don't harbour resentment now, but my parents were quick with their hands - and I became one of those kids who don't even flinch. Because it didn't work. Maybe the first few times it's a bit of a shock, but after that you start to realise that there are worse things. As I got older, I knew I would rather get a smack than be grounded, or have something taken off me, or be sent to bed early, etc, and frankly my parents would sooner have swung for me anyway because it was easier for them to follow through with. When I got to probably about thirteen, I started to see it as disrespectful, and I hit my mum back a few times, which resulted in full-on fights.
I think, if any method of parenting is "ineffectual," then it's using violence in place of teaching reasoning and a sense of consequences. After all, in the real world, it's very rare that someone will hit you for doing something wrong, and kids should grow up knowing that it is absolutely not okay for anyone to hit them, or for them to hit anyone else.