It's worth raising.
Every Pokemon is.
Seriously though, Swoobat is quite good. Not amazing, but it's unique and can surprise unprepared opponents.
- Both Simple and Unaware are decent abilities
- It has above average speed
- It has decent Special Attack.
Using Calm Mind with Simple raises both Special Attack and Special Defense by 2 stages at a time.
Couple that with the moves Stored Power and Air Slash, it can quickly take care of a few Pokemon on its own.
Plus, it has decent coverage moves in the form of Signal Beam, Giga Drain, and Heat Wave, so you can surprise your opponent. It can also set up Reflect and Light Screen to help you with, which works great with its high speed.
Finally, at the risk of sounding cheesy, I'll say it again: Every Pokemon is worth training. (Yes, even Hoppipp.)
Battling is about having fun, so don't let some Smogon douche convince you not to use it. After all, the guy who won the VGC used, of all things, a Pachirisu, and awed the world with it.
"Using you favourite Pokemon is the quickest way to lose the meta?" Some Kangaskhan or Rayquaza fan is snickering at that. Besides, battling is more about situation than stats (Although, it is about stats as well, and to be honest, Swoobat's not very high on there), and you might run into a spot of trouble every now and then, but catching opponents off guard is a good way to win. Don't give up on Swoobat yet. Try it a few times, and a few more times. Then, if you feel it's really that bad, then get a replacement.
On a side note, please ignore the Swoobat image I just googled up. It's from miss eliza rose on DeviantArt.