The lesson we learn is that though crypto industry is developing very fast but still far from maturity so stay away from centralized exchanges until they are properly regulated and scrutinized to protect investor's fund.
This incident has massively damaged the reputation of all centralized exchanges and people to think twice/thrice before they transfer their funds in any exchange including Binance which is top rated exchange. People didn't like the role CZ (Founder & CEO of Binance) played; in the beginning he came up with rescue plan but later he backed out.
Conclusion: Though this fallout is a pain for the short term for the whole crypto industry, but I think it is good for the long term because more regulation will definitely come out now to scrutinize the crypto holding companies.