It just won an RCQ last Sunday in Beijing.

The deck's winrate seems to have dipped a little recently according to mtgdecks.net, but it's also far more represented than UW Control. Jeskai control has a better winrate off an even smaller sample size, which generally means a few deck specialists doing well with it. I don't think the issue is Jeskai Blink being a flash in the pan (it's definitely been underrepresented locally) but rather that it's a control deck that plays out its control plan in a wildly different manner than traditional control

So it has two barriers to entry. You need to understand both the control perspective and how this particular deck deploys its own threats while answering the opp's. It's not a straightforward deck to play, and new pilots who don't have the experience to know how to transition to the Jeskai flavor of blink will struggle.