A lot of these kinds of analyses assume perfection throughout the lineup.
Here, the statement is that speed in a lead off hitter isn't that important because the hitters coming up behind him are the most proficient on the team.
We've seen, however, that this kind of text book analysis doesn't necessarily translate. Every team doesn't have great middle of the order hitters. And even very good ones can leave a bunch of runners on base.
On the Reds this year we've seen a plethora of men left on base in key situations. and so many baserunning errors. Sometimes, that extra speed, that stolen base, that successful extra base, would make a difference.
The Reds need better team speed, not only Hamilton. But he would be a big first step. The key with Hamilton will be teaching him to use his speed by hitting grounders, slapping the ball, drawing walks, making contact. He will not have to be a great hitter if he can master these skills.