I admit I like to use special effects, and yes it is easy to overdo it.  Carrara itself provides a lot of options, but for some situations, I like Particle Illusion.  PI is a 2D effects program that can overlay any still or video, and has many, many presets (called emitters).  Lots of demos at their website.  But the work that comes out of ILM has been amazing for years, ever since the original “Star Wars”.  Here is a highlight reel:

http://www.usatoday.com/story/life/2015/06/12/industrial-light-magics-greatest-special-effects-hits/71062124/

Particle Illusions, or PI, is an excellent piece of software for FX generation!

Here is a low cost alternative to PI: Timeline FX

One great advantage of Timeline FX over PI is that it can generate seamlessly looping FX'es, which I don't believe PI can.

That does look like a good value, $46 vs. PI @ $389.  And it looks very similar to PI, using emitters, etc.  One thing I don't see is the ability to use a still or especially a video as a background.  That is a good thing to have when you want the effect to track something in the video, e.g. a smoke trail behind a vehicle.  Did I miss that?

The looping sounds good, I think PI can only extend the "life" of an emitter, maybe giving a similar effect.