Especially since it's the only Wisconsin State Highway that traverses the whole county from East to West vs in Lake County IL there are several choices.
I still prefer one WI-50 over the several inadequate IL routes, IL-173, IL-176, and IL-120.
It's not that they're inadequate, if people knew how to drive they would be fine, especially 176 through Ivanhoe. So many drivers are terrified of those curves and hills. WiSDOT doesn't know how to properly time and synchronize the traffic lights. You'll stop at every single light on both WIS50 and WIS31.
Sorry, but no. All three IL routes are terribly inadequate. IL-120 is partially a freeway, but it unceremoniously ends as a 2-lane in Wildwood and then proceeds to be a horrible drive westward with dozens of traffic signals, level RR crossings, etc. IL-173 and IL-176 are pretty much that way from end to end. WI-50, OTOH isn't perfect; there are lights here and there and there's the Paddock Lake speed trap that brings a little slice of Mississippi into the north. Nor are drivers in Wisconsin in any way superior to Illinoisans. To the contrary, given the horrible lack of driving skills I see on display here on a daily basis, I actually wonder if there even is drivers' ed in Wisconsin. But I digress....
In summary, WI-50 s a lot faster and when I lived in Lake County, I'd literally drive 15-20 minutes up I-94 to catch 50 for the ride west if I had to travel somewhere like Lake Geneva or Madison or Minneapolis. It's way better than any option on the Illinois side, which is horribly lacking in decent east-west routes.