Lol did it solve anything though?

If you actually watch the full episode, the timeline of events is:

• Someone rents a new house and finds a skeleton in the marsh behind it. It's a ~30 year old woman who died in the winter and was bludgeoned and stabbed repeatedly.
• They send away for DNA sequencing but the lab doesn't get back to them for like a year and half.
• In the meantime they look at missing persons cases (over 100 in North Carolina they state, though presumably ~half that once you filter for skeletal women)
• They determine that this woman's case seems most likely based on all the other details about her case. The forensic tech who's oddly interested in how much pain people feel as they die is interested in using "impose an image of a skull on a face technique" to see if it matches.
• She reaches out to a skateboarding computer science professor who uses gimp to paste a semi transparent layer of the skull on top of a picture of that victim's face and thinks it probably maybe matches.
• They get fed up with the DNA lab and send it to a second one that responds in three weeks confirming it was who they thought.
• They talk to the victim's friends who point out what party she was at the night she disappeared.
• The people at the party say that she was hanging out with this one big truck driver after everyone else. His story has been that she walked home after everyone else left, in January, for 7 miles.
• They interview him a few times and he eventually says that they had sex that night and she belittled him for not getting it up and he pushed her and she he hit her head on the nightstand and he left and she was fine when he left.
• He's convicted of murder and dumping her body because that's an obvious crock of shit.

Kinda feels like the whole GIMP escapade was just a waste of everyone's time and all it took to solve the case was basic police work in terms of interviewing people who saw her last. By the time they tried GIMP they already had a prime missing person that they thought it was, and they wouldn't have had to try gimp if they just went to a second / competent DNA lab immediately. The way they present it is a little unclear, but it sounds like they didn't even pull the suspect in for further interviewing until they finally got the DNA confirmation for who it was.