Builder pre-launch offers are mostly a trap, not a discount.

I'm seriously looking at a 2BHK near Sohna Road, maybe a Signature Global project, aur they're pushing this 'early bird' pricing. They claim it's 10-15% cheaper than launch, but honestly, what if the market doesn't appreciate as much? My parents keep saying wait for ready-to-move, but then prices badh jayenge. I saw some M3M projects on Golf Course Extension Road; their pre-launch was so hyped, but launch ke baad prices utne bhi upar nahi gaye. Matlab, is this 'discount' real or just FOMO create karne ke liye? Should I just wait for OC, ya is early entry actually worth the risk for potential capital appreciation? Confused hoon about the real ROI.