I wonder how often that one switch is plagued by delays which turn those 15 minutes into significantly longer times, and cause propagating delays throughout the system.
If you have tickets for a family with seat reservation, any problem with the switch can be very annoying, especially if the second train is full. It’s definitely not the same as direct train.
That Russian train was optimized for long distance experience and had sleeper cars. It was pretty good and could have been better if it was traveling the same speed as the new train. We need more of such trains in Europe.
They only compare to some strange, Russian direct train.
The reference should be the current best connection, which would have one train switch.
The difference between this new connection and the fastest connection with one switch is ~15 minutes.