I don’t really get what makes this an amazing IPO. Afaict they left 33% of the money on the table. How is that a good thing for the company or the shareholders?
The company doesn't necessarily raise that much on IPO day. The importance of raising that sum at a 20% higher/lower valuation probably isn't the biggest thing at stake.
The IPO isn't primarily fund raising, especially for this current crop of more mature unicorns. It's primarily liquidity generating.