Vienna to Prague via night train? Feasible?

Do you consider a four hour train ride as "wasting time"? I just looked at Seat61:
https://www.seat61.com/trains-and-routes/prague-to-vienna-by-train.htm

We've always enjoyed our train rides but we don't have Amtrak here so it's a novelty to us. I'd think the bigger question is what you might miss in Vienna or Prague by shorting yourself on time in each of these cities. Are you the type to hit every tourist site in the book or do you just like to wander around, get a feel for the city and enjoy some good food? We've never spent a week in a single European destination and splitting our time works well for us, but I'm sure we've missed a ton.

From Vienna toward Prague, the timing of the overnight train is a bit early, arriving at 6:00 a.m. In the opposite direction, it arrives at 7:00.

You have a week, with the main purpose of hitting the Christmas markets? Then why are you going to Prague and Vienna? One city a day?

Frankly, the Kriskindlemarkt's are best after 5pm; that's when the locals start to outnumber the tourists. They're not for shopping, they're for socializing.

If you only have a week, and you have to go to Prague and Vienna, fly to Nuremberg, take the train to Prague, and then train to Vienna and fly home. I've done that same itinerary, but over the better part of 3 weeks.

For a week that needs to be spent shopping for Christmas trinkets you could spend it all in the triangle between Wurzburg, Bayreuth, and Nuremberg and not see all the places.

When I looked at train schedules itineraries were giving me 7 hour options. That’s what prompted the overnight idea; spending a full day of a one week trip would be a poor use of scarce resources!. Of course a four hour train journey changes the equation.

Vienna and Prague are only 4 hours apart by train; too close to use overnight train (which costs quite more). You can do Prague and Vienna in one week.

Schedules are currently published through Dec. 8. Looking Up Train Schedules and Routes Online gives you the Deutsche Bahn train schedule link and tips for using it (though it doesn't sell this ticket).