in this instance refreshing during banish is the same as a big hitter waiting for 30 mins before hitting cerb so the smaller players get the max coins they can get before you pummel it in one hit...
Each round in banish is weighed at roughly 1.5 - 2 minutes, from hit to hit, that means you are allowed a hit every 1.5 (- 2) minutes, if your round continues for 4-5 mins like some peoples do then they are missing out on 50-60% of their hits, refreshing is the only way to guarantee you will get all the hits you are entitled to....
If however there was no downtime after refreshing it would be an exploit, trust me, i have looked into this..