If Laura decided late on that she couldn't manage some of the planned dance because of her ankle then Giovanni's two showboats to fill in would make sense. The pity is that he didn't think to do them "showing off for Laura" - facing her, or dancing around her, while she samba'd on the spot looking sultry and haughty.
Laura seems to have been very professional about appearing with an injury, as it would have been a big problem for the producers to have a second withdrawal. She didn't complain, didn't ask for a bye in the dance-off, didn't pick up her skirts and show a knee brace during her final dance.
If her ankle hadn't healed more than two weeks after the initial injury, it seems to me that it was likely to be an ongoing problem for the rest of the series if she had stayed in, so the scope for keeping Laura in for much longer by giving her an easier dance would have been pretty limited.
I did think that Laura did well in the dance-off.