It seems to me like this is a classic case of you needing to do what you want to do, regardless of what an online map says. I-80 would be the direct route and it would be the fastest, but it doesn't mean it would be the best route for your trip.

I don't know if your trip will be more entertaining if you go via Vegas, if you're just looking for a place to gamble and see lights for a night and if you have a limited timeframe, Reno would be right along I-80 as an alternative. There are also plenty of other interesting things to see along the route, depending upon your interests.

But Vegas is a great city, and if you went that way, you could also take a trip through the Colorado Rockies or stop at any of the National Parks in Utah. All of those things depend upon how much time you have and what you hope to achieve with this trip.