Do they have a chance to improve their world standing and potential warmup group at the Olympics?
Two considerations are 1. Can they get into the last warm-up group and 2. What would they need to do to protect staying in the penultimate warm-up group. They are currently 8th.Z/K can earn a maximum incremental 412 at 4C's, because they'd need to drop 428 for best 2/3, which is 412 for 1st through 18 for 7th.
Looking above them, no one can catch the Top 4, F/G, C/B, G/F, and L/B except #5, G/P. If G/P don't go to 4C's, #6 C/P aren't going, #7 R/A could knock down G/P to 6th with a win at Euros; they will earn some points for 5th or above. #8 is Z/K, who, are 171 behind R/A; they can't catch G/P with a win, nor can anyone below Z/K. So jumping to the last group is a non-starter for Z/K.
Looking behind them to see what could knock Z/K out of the penultimate group were Z/K not to skate: Z/K would pass R/A if their placement at 4C's is at least three above R/A's at Euros. That wouldn't move Z/K into a new group, nor should it change the any split draw. That is actually doable, since R/A need to be 5th to earn any points, and they are competing against FB/C, F/G, G/F, L/B, S/D; the last four plus T/V beat them at Euros last year. Even if the top three Canadian teams skate, the field isn't overwhelming at 4C's, while Euros could be a bloodbath.
Were Z/K not to compete, there are three teams that could surpass them mathematically but only with a win -- D/S, T/V, Taschlers -- and all three can't win. S/D, who only have to drop their lowest 126 points, need 19th or higher to earn any points, and they would move past Z/K if Z/K didn't earn 4C's points. L/L could surpass Z/K if they compete at 4C's. Unless all three things to happen, which is hugely unlikely in the current Euros field, Z/K should be safely in the penultimate group without competing.
So either they're playing it really, really safe, or they want the experience and cash and prizes.
ETA: A win at 4C's is 840 points; silver is 756 points. Z/K would have to be 4th at Worlds (875) to earn more than 840, or 5th at Worlds (787) to earn more than 756. None of that is impossible if the top half of the field aside from C/B isn't planning to be in to win an elusive World title, but if FB/C decide to compete in Prague, it might clear out some of the field, and then it's jockeying for position among L/B, L/L, Z/K, maybe C/P, maybe S/D.