Sohna pre-launch deals: are they worth it?

Did a site visit to a Krrish Group project in Sohna on Saturday. They're pushing pre-launch rates, saying it's the best deal. But my parents keep saying builders inflate these. Is early-bird pricing actually a discount, or just a marketing gimmick? Also, they're offering construction-linked payment plans. Is that smarter than a typical down payment for an investor like me? Not sure if it makes sense to block funds early. What's the real ROI difference?