Yes Smithman had to keep his alibi i.e. being present at the tapas bar. He couldn't lose that so he couldn't be at the beach and the tapas bar at the same time. So to keep his alibi the first move was enough to get her a safe distance from the apartment. The 2nd move to further away was done when he had more time to do it in the chaos and confusion of the first searches but he was moving quick with the child as witnesses noticed. So he didn't want to be missing for too long or caught in the act.
If Smithman was Gerry carrying Madeleine, then I have always thought it was an incredibly risky move. But I suppose that a parent carrying a sleeping child in or near the resort at around 10pm would be quite a normal sight going back from the creche, for instance or going back to an apartment.
But it is hard to see what excuse he could have if, say, he had bumped into someone who knew him and who stopped and talked to him. How would he explain carrying a sleeping child AWAY from the resort at that time of night? What would have been the excuse?
Still, as others have noted, desperate measures, perhaps. Also, it would be incredibly risky to involve others in the initial carrying away of Madeleine as people will talk - eventually. And an accomplice to a crime who fesses up is going to get off a lot more lightly than the key players in the whole thing. Theoretically speaking, of course.