“Hmm, I like being loved and praised and fed milkshakes here in prison, I’m going to keep talking, even if it isn’t true!”
There is a mutual relationship here: Little gets company, attention, and praise, police get to wipe 57 cases off their books that they have no intention of ever trying in a court, and this particular investigator gets lionized.
edit:
> After the confessions came the painstaking work — confirming killings. There won’t be time to prosecute Little for all the deaths, but authorities believe they can sufficiently tie him to a homicide to consider the case solved.
This is the entirety of the content detailing the confirmations that I can find in the article.
> By his count, Holland and his team have confirmed 57 of Little’s 93 confessions, not including 21 in Southern California
That's a definitive statement. I agree that it would have been nice if the article had included a bit more regarding how they were confirmed (assuming it's reasonable to release such information - even if vague - at this point, as it may not be).
These techniques may be useful for serial killers (although we don't know, there's no research) but we know these interrogation techniques have caused many miscarriages of justice.
Personally, I'm not bothered by building up the serial killer's ego. The important thing about imprisonment is that he's prevented from killing more people.
Bringing closure to the people involved in those deaths is worth being nice to a serial killer.
Maybe sometimes it's better to get very unreliable information and try to confirm it independently, the classic example being if they say something only the killer would know like where the body is buried.