Sanders is fine with no news from Iowa, the next primary is in his backyard and he has nationwide name recognition.
Buttigieg on the other hand needs Iowa to be huge for him, and this fiasco certainly hurt that strategy.
If they released the vote totals on time and Bernie won, that would have given his campaign momentum, which could have lead (still might) to a NH blowout.
Instead, Pete got to "declare victory" twice -- night-of, and again after the 60% release. Now it really doesn't matter if they release the results and Bernie is shown to have won, because we're already multiple news cycles away from caucus night and most people aren't really paying attention, so it's going to be hard for Sanders to capture any momentum, if it's shown he has won. Pete, on the other hand, got a significant NH bump from the IA results in the latest polls.
I think the only way it's hurt Pete is through IDP incompetence, where to most Americans (who hate a cheater and love a conspiracy theory) it looks, for lack of a better term, extremely shady. It's also fired up Bernie's base of die-hards, who are now on the warpath (or even more so) for the early states
If the winning number of SDEs does flip to Sanders by the time they're all counted, though, that'll be pretty damning.
I'm currently on the "no conspiracy" train, since a caucus is pretty hard to fabricate.
Sanders may yet come out ahead when full results come out - the betting markets put it at 25%, so the theorists might yet be right that the delay hurt Sanders the most (not necessarily right about their theories, but I sympathise with the general level of paranoia - although an given theory probably isn't correct, I think those dismissing them all as crazy lack imagination).
Arguably, since by all accounts Sanders performed much better than Biden (who is seen as Sander's main competition, not Buttigieg), it's still relevant that the delay hurt well-performing candidates in Iowa (Sanders and Buttigieg) and benefited poorly performing candidates (Biden).