"Keywords" are a special text that represent an ability enclosed within a red/white box. They work as a form of shorthand in order to save both space on the card text and time when reading them. Also, they can be used when a card will be get/lost one or more of these keywords.
In card texts, a reminder text about the keyword can be included. That is, a parenthesized text which explains the main funtion of that ability. However, the reminder text itself has no real effect on gameplay, but illustrate rules to the players about how that ability works.
In other words, some keyword might shorten the card texts.