D'uhh. To use as bargaining chips.
Sooooo even a very biased person can appreciate the fact that from day one getting the hostages back was one of the 2 stated goals of Israel, along with demolishing Hamas. It was just as important to Israel as it was to the US when they wanted the hostages back from Iran. As well, keep in mind how much pressure there was/is in Israel on the gov't to get them back, as evidenced by numerous mass public protests.
Maybe when Israel launched the raid on Entebbe they didn't really want the hostages back. It was only a publicity stunt and they just got lucky.