A continuous constraint hands back a number — say, how far a candidate strays from an ideal. But a number isn't a violation yet: a step is missing, a link function that turns the raw value into a penalty. Pick the link and watch the same value become very different violations.
Downstream, the grammar turns weighted violations into probability by exponentiating them. So the link you chose up above reappears here: it shapes the whole predicted distribution over the vowel. The buttons swap the link; the weight sets how severe it is.