The victim wouldn't even know the key was cut by this service. So the friend/plumber/handyman or whoever could just take the picture, get the key cut and then raid the place without anyone knowing.
Indeed. In Germany for example, employees of this company could be tried as accomplices to the crime if it was found that they had duplicated a house key without asking for proof of residence.
This sounds extremely complicated compared to the somewhat more realistic "throw the jewelry in the toolbox and walk out" or the "unlock a window" approach. The most realistic approach is to lie to the customer... "well, we need to special order a left handed crescent wrench and some frequency grease and also do some mold abatement". This is before we get started with outright insurance fraud and the like.
It could happen, but it sounds a lot more like a hollywood movie plot security threat than a real security threat.
Seems legit.