To be specific: they did a DLP, not an IPO. Underwriters make sense for IPOs, because the company is raising money. There's no point to an underwriter in an DLP, because the company isn't raising money.
They were not under requirements to hold an IPO; they were required to provide public liquidity to their shareholders. That's why they chose a process that involved no underwriting. And that's also why their case doesn't really provide any generalize lessons, because those types of terms are incredibly rare in growth-stage venture financing.
