What kind of threats can these top-notch weapon help Egypt with?
(in particular, threats that less sophisticated weapons would not have been able to handle)
The main threat Egypt faces right now is ISIS affiliated militant groups in neighboring Libya.
However, I suspect the purchase has a lot more to do with diversifying Egypt's fleet, than with helping them deal with imminent threats. Egypt is largely dependent on the US for its defense needs and was put in an awkward position when US aid was suspended after the 2013 coup. Although the relationships between the two countries have since been restored, it wouldn't hurt Egypt to have an alternative source of military equipment.