You'll get a good job with CDAC or and without it you'll get a good job as well. CDAC is just for honing your skills further and most of the R&D firms consistently lookout for candidates with extra qual.
Yeah its not easy at first but if you can manage it, its worth it!
Reputed companies have a policy of hiring candidates with 60%+ throughout with no backlogs.
Be it with or without C-DAC.
Also placement of WimC is lesser compared to DAC. Unless you specifically want to do WimC I'd recommend you to go for DAC.
About the basic question my answer is you don't need to do C-DAC since you will get the same job as you would get now. Your academic marks are looked at in CCPP(C-DAC Centralised Placement Program) as well.
Only if you have throughout 60%+ will you get better placement from C-DAC than you will without it.