Ancestry, the genealogy and DNA testing company, has digitized millions of records of people who were displaced or persecuted in the Holocaust and made them searchable online at no cost.

The announcement this week drove numerous genealogists to the site to try to fill in longstanding gaps in family stories. It also spurred a debate about whether enticing people to sign up for a for-profit database with such sensitive public records was appropriate.

Rachel Silverman, a private genealogist specializing in Jewish family history, said she was enthusiastic about the development, but added that it was too early to know how useful the records would be.

“Every American Jew has people they lost,” she said. “It’s just the matter of the degree of separation.”

The release includes passenger lists of millions of displaced people, including Holocaust survivors and former concentration camp inmates, who left ports and airports in Germany and other parts of Europe from 1946 to 1971. It also includes records of millions of people with non-German citizenship who were incarcerated in camps or otherwise living in Germany and German-occupied territories from 1939 to 1947.

The records will not tell people who they lost in the Holocaust if they don’t already have an inkling. Instead, the records could provide additional hints at why a relative took one escape route instead of another, Ms. Silverman said.

“In genealogy, the almighty why is the hardest,” she said. “Why did my family end up in Atlanta when they were from the small town in Germany? When we find out how travel was arranged, that might open new doors.”

Allan Linderman of Newbury Park, Calif., for example, had researched his 87-year-old cousin’s journey to the United States before the documents’ release. Born in Poland in 1932, the cousin, Irving Rock, and his family fled their home in the early 1930s. They then spent more than a decade scrambling for safety, moving from one place to the next. Because he is still alive, Mr. Rock offered some details from memory. But in the trauma and chaos of relocation, he could not recall when precisely he left Germany for the United States.

Searching the new collection, using the original spelling of his name — Icek Rak — Mr. Linderman found his cousin. The ship departed Bremerhaven, Germany, for New York on Sept. 7, 1949.

Beyond curiosity, this information is useful, Mr. Linderman said. The German government and Dutch railway offer some financial compensation to victims. But they require documentation.

“This is another step in trying to get some reparations,” he said. “These are people who cannot prove the things that the German government requires because they spent all this time hiding.”

Both collections were drawn from the Arolsen Archives, a longstanding collection maintained by the International Center on Nazi Persecution. A portion of the archives was previously digitized. Yad Vashem, the World Holocaust Remembrance Center, also maintains digital archives.

Looking at the marketing materials, however, one might think that Ancestry was the first entity to digitize Holocaust records, said Yonah Bex, an archivist in Los Angeles.

“It’s not like Ancestry uncovered a new data cache,” she said in an interview. “They’re not Indiana Jones.”

And even though Ancestry is offering these materials at no cost, Ms. Bex said she was skeptical that the company was motivated by altruism.

Ancestry representatives took issue with this critique and pointed to portions of a previously released statement.

“The release of this record collection is part of Ancestry’s philanthropic initiative to make culturally important records available to everyone,” the statement said.

And not only are the records free, the statement noted, but the company has also donated digitized copies to the Arolsen Archives, Yad Vashem, the United States Holocaust Memorial Museum and other entities to post on their websites as well.

For Ms. Silverman, the genealogist, motivation is irrelevant. Ancestry maintains one of the largest databases of DNA profiles and family history data in the world, making more than $1 billion in revenue in 2017 alone, according to the company site. Its financial model is built on getting millions of people to subscribe to its family history sites and pay for its DNA tests.

“It would be silly to say it’s not a strategic business move,” she said. As an “elder millennial,” though, she said she appreciated that getting the material into a searchable state required money. Her bigger concern, she said, is whether it will be useful.

Ms. Silverman said she had a client who wants to trace the path of his grandparents to Canada from Germany. She searched the new database and came up empty-handed.

She did find something that showed which Jewish organization sponsored the journey, but it was in the subscription database.

Still, successful or not, at least these searches don’t require travel or waiting for months for overstretched archivists to manually pull something up, said Marlis Humphrey, the former president of the International Association of Jewish Genealogical Societies. In the past, she has flown to Israel from Florida to look for records.

“This is unbelievable,” she said. “We can get the records in our pajamas, and if we didn’t search right the first time, we can search again.”