I'm too tired to look up the legislative memorandum right now, but that statute was based, nearly verbatum on another statute (CPL §160.50) that seals records when a case "terminates in favor of the accused" i.e. the defendant is acquitted or the case is dismissed. The intent there was to protect the acquitted from the stigma of their case.

Similarly, 160.55 was passed to protect people from stupid, petty bullshit that happened long ago. It was passed in the mid-to-late '70s, IIRC, at a time when the kids of the 60s were grown up and looking for real jobs only to be confronted with a ticket for discon from some demonstration 10 years prior, or smoking a joint in the park, and having that as an impediment to getting a real job.

When I was the Freedom of Information Law (FOIL) Officer at a certain Govenment Agency, I'd get calls all the time from people, now in middle age, who are changing jobs and all of a sudden a doob they toked thirty years ago has come back to haunt them because some of the records had been improperly sealed, or rather not sealed at all.

The prohibition against secret trials is to protect the accused. So in that sense, the statute does not run afoul of the public interest.