After a player performs a successful cascade or Septimus Divergence, a simple looped move is unlikely to be a sufficient response, which means his opponent must first use a token sink to soak up some of the excess tokens. Clearly, such a response requires at least two moves, and so the net effect is to hand the initiative to the player who triggered the cascade.
Advanced players who do not intend to use a multi-token strategy prefer to use King's Cross and the other token sinks pre-emptively, thereby stopping large token balances from accumulating in the first place.
Note also that King's Cross is adjacent to the major holding station of Euston.
[SM]