It depends...
It depends.
Talking football -
In the current state of football in the SEC, the winner of the SEC West is usually the strongest contender for SEC Champ - but not always. Assuming that the other teams (mainly Alabama, LSU, and aTm) in the SEC West stayed at their current level, that would mean that MSU would have to better than them to win the West and would likely win the SECCG. If we did that, we would most likely play in and win the National Championship game, too. If they stayed at their current level and we improved enough to be better than them then we would most likely be the best team in the nation.
On the other hand, if the reason we won the SECCG was because the "elite" teams had gone down in ability and we stayed at our current level so that, by default, we were the best team in the SEC West, then it is most likely that another team in the nation would be better than us. In that scenario, we wouldn't even make it to the National Championship game, much less win it. So in this case, winning the SECCG really means nothing. If that is the case, I would rather have the National Championship in Baseball.
Since Baseball (and Basketball) are more of a true playoff championship series (at least for the time being), our winning the National Championship in Baseball is more likely to mean that we really are the best team in the nation. Football matchups tend to be selected as much as or more than earned.
Every year is different; some more than others.