the x10 epic orb were only in the Anniversary month PoA. Considering the average epic days cost per guy, just the two premium guys cover the 7200 kobans cost (since one guy during epic days drops with 333,333 fights, on average, that corresponds to 3600 kobans)
If you want to consider the 200 free fights you can have during the 4 days epic days last, you'd get two guys at a 5040 kobans cost, but there are all the others rewards that covers the cost of the premium path. if you don't want to consider the value of energy points (agreed), single game pachinko orbs (agreed for the single mythic ones, questionable with the single epic ones), and combativity points (questionable, even more considering that you don't need them to complete the path and you can claim those points on last day of PoA and have some more CP for the shortened main event. 65 CP are a little more the 3 refill/ 650 kobans), just consider the x3 and x6 games mythic pachinko orbs. In combination with those you get for free path, they sum up to 105 guaranteed shards in mythic pachinko. if you use in a favorable rotation, that's a whole bonus guy).
TL;DR: The premium path is worthy of that expenditure. The only PoA premium path that wasn't worthy of 7200 kobans was the very first one.