I'm not surprised it was the biggest, as it's a company that's already known to crypto users, so there's a minimum risk of getting scammed, and they have 56 million users, so a huge community of people behind them. These two things sound promising enough to invest it because reputation + a huge user base almost guarantee the price will skyrocket. But that's a public offering, so it's about selling shares to people. That's what might have gathered attention not only of the crypto community, but of big stock traders as well, since getting into something crypto-related and yet familiar is getting more attractive to them.
Tech stocks have given good returns ever since the pandemic started. Top stocks such as AMZN, FB, TSLA and MSFT have given huge returns during the last 18 months, and I strongly believe that Coinbase also benefitted from the prevailing positive atmosphere. The markets are at all time high now, and a lot of experts claim that a correction is due in the near future. It will be interesting to see how new stocks such as Coinbase perform under such a scenario. And BTW, in case of Coinbase it was not an IPO. They went for direct listing. Please correct me in case I am wrong.