When elections don't matter

Democrats lost Anthony Weiner's former seat in the House of Representatives in a massive upset.

I follow politics because I love it.  But let's be honest:

This election doesn't matter.

1. If you don't vote for Weprin (Democrat) then the Republicans will take over the House?
(they already control it)
2. Your vote won't determine a major issue like 2010's Scot Brown's Senate race with healthcare.
(it passed even though he was supposedly sent to stop it)
3. This is a temporary political embarrassment to President Obama, that won't matter unless it does.
If times have changed, and Obama doesn't win, then the results last night will have been the first sign of it.
But until then, this is just another vote in the HOR which votes as a party on pretty much every issue.
There's no real difference between 230 republicans and 231or whatever the number is.  The Speaker only brings items to be voted on that have a majority of the majority unless it's an agreed deal between the parties.

If Obama wins in 2012, this won't even be a footnote.
On the other side, why vote for the Democrat?  Times are tough.  Why shouldn't you want to send a message to the President that has no real world meaning? It's not like you're voting to end your job or lose a precious right.  In addition, the Democrat "runs away" from the President during tough times (based on bad polling); how does that inspire confidence in him or the President?

Is this good for democracy?