i think it should be entertaining for the guests. there's nothing worse than just swaying on the spot.
i went to a wedding where they did a choreographed dance to a fast song, which was supposed to be funny but ended up being cringeworthy because the couple just wasn't into it. it was like they were embarassed or something. i found out afterwards that they were really nervous because they'd only had 3-4 lessons.
i think that if you're going to do it, do it properly and make sure you pull it off.