Why was he taken off the first line and benched today?
Because it was a tough game where their goaltender and Marchenko have put them in a 0-2 hole with two hilarious brainfarts.
Samonov on the PP at 0:21
Marchenko at 0:45 must've thought Samonov needs another confidence boost
So Bragin basically decided to rely heavily on vets to save the game. It was an a case unususal for the KHL with top line forwards playing over 20 mins. In the end it wasn't enough. Bragins was quoted before saying that Michkov is not yet 100% ready for the KHL speed and toughness. Probably a good thing to not throw a 16 year old to the wolves just yet. Let's for all the admiration for Michkov's talent not forget he is still 16.
As I wrote before I fully expect younger guys to sit entirely or get limited minutes in games against better teams and get alonger leash against weaker opposition. The both youngest Michkov and Chibrikov got significantly under 10 mins in that game.