I voted no. IMHO it's not an effective attack by itself, and it's not meant to be. It's a good way to practise the basics in Aikido, and it's and ok technique to to followups from. But no way do I find only the grab as an effective attack. Sure, you can break ukes balance. But then what? You have to move on to another technique.
Perhaps if you're really strong, you can pinch his hand off? THAT would be an effective/impressive attack.
PS. I saw a movie a few days ago. A man grabbed another mans hand (gyaku hanmi katate dori!) and put out his cigarette in his palm. Ouch!