If war goes for 65 days then then it will be all back. But still it is a worthy card to collect.
For hive rewards if you will have 8000 SIM Power (30 day average Sim holding) then you can get them. Those are not too much but about 25% ROI.
If you can get your city to top 400 cities by population , you will earn hive rewards too.

In my experience, focusing on hive rewards cost too much with much return. Better is to build a high SIM income city that's you you can get most returns.