Are they?
Düsseldorf-Munich for 26,70€ including reserving a seat.
Kiel-Düsseldorf 29,90€. To get back, 26,90€.
Kiel-Munich and back for 53,80€.
Not even Ryanair is that cheap, especially when you consider that with trains you don’t have to go through security, have none of the check-in times and other bullshit, and can take luggage without paying a 60€ surcharge.