Quoting ATW- "For JetBlue it's about the money; for Lufthansa investment may mean more"

JBLU's liquidity is an issue with high fuel price + debt maturing. So selling out is the natural step, and who can beat an European buyer with inflated currency.

The downside for JBLU are two-folds
1. It will play with StarAlliance rules more or less, sooner or later
2. LH will eliminate the probability that JBLU establish a full range of connecting service with ALL carriers into JFK, which might be the best way out of the woods

The upside for LH are two-folds as well
1. A great call option on JFK assets and airbus+ Embraer aircrafts
2. A great beach head for assaults under Open Skies