In practical terms, it means that they don't have to worry about being eliminated this week. In bigger terms though it's a "we liked what you did"/"kudos" from your former competitors, and it's hard to beat something like that.
Thus far it's been tight every single week, and this time was no exception.
In the end though, they selected beautyofgrey!
Congratulations on your immunity and your guaranteed spot in the Top 13 of Season 6!