is it worth the 800 gold frags?

quite new to the game and i was lucky enough to pull ex kizaru in 1k rds and already spent ~160 frags getting him to lv80. is it worth the additional 800 to get him lv100? havent played long enough to know whether its worth it for the extra medal slot + stats or if its better to just save it and wait on a newer units and just stay using lv80s instead of lv100.