I’ve played a lot against Marcel’s bot (he is one of the organizers). The thing is MCTS based and very fast. It doesn’t care about strategy. Strategy is an interesting aspect for human players though, since the dilemma is thematically embedded: more stones = more points, more groups = less points, and the fastest way to get more stones is to have more groups ...
P.S. The bot appears far stronger than the Havannah bots. There may be several reasons, me being wrong about Symple’s programmability included. But then, I’m not as good at Symple as I am at Havannah, relatively speaking. I agree it is an interesting contest :) .