You should definitely participate in the upcoming ones. From my experience, and I was carefully examining every entry in each Roobet Art Contest, professionally made artworks always have good chances of winning a prize(or even two). That doesn't imply that complete amateurs like myself shouldn't try to participate, though. I believe some times it's enough to just make the grand jury smile with your work, and the prize is yours. 
Now I'm intrigued to see your art submission to the contest. Hope we'll have another one soon.
Yeah planning on to take some extra time during the upcoming art event on roobet to give my small entry but not so sure that i can manage during that time or not.But will try my full to submit atleast one entry as the rules say you can submit two different artworks.Yes sometimes a simple artwork could be more impressive than a more advanced one as it depends on team whose art they like the most and yes will try my best to come up with something good in upcoming one to intrigue you Now I'm intrigued to see your art submission to the contest. Hope we'll have another one soon.
I've had also participated in the past in an art contest for Roobet and I must say there are really a lot of good participants.
Nevertheless, I would advise everyone to participate if you have time and desire to spare.
Because I think in a competition it is not primarily about winning, but about the fun.
And if you really win a prize it is a nice bonus...