My wife and I visited Ivrea in January 2018 on a sunny winter's afternoon. It's an easy one hour train ride from Turin's two main stations, and trains leave about every hour. The (proposed) World Heritage area is adjacent to the train station, and everywhere is fully walkable.
There's a nice trail of information signs, talking about the Olivetti company and its eponymous founders - the main employers for the town in the 20th century. The large factory building is very impressive and reminded us quite a bit of the Van Nelle factory in Rotterdam.
It seems the town has rebounded a bit since Els's visit, as the main factory building is now occupied by offices for Vodafone Italy, and a few workers were buzzing around (though we visited on a Saturday). The area we walked around did have a lot of closed shops, but it didn't seem particularly grimmer or worse-off than many other areas in Italy.
We were a little disappointed in the crescent-shaped building, as there's not really anything to see since it's built into the side of a hill (and there's large NO TRESPASSING signs). Though I guess all the windows look into the centre of the crescent, and I can imagine the residents don't want visitors peering in!
Overall we enjoyed our visit. We stopped to read all of the information signs, and our visit took about 2 hours all up.