Battling in the Campaign Tower can be another great way to get rid of your Gems during the Gem Event. While it's usually not as great as Marketplace purchases, it can definitely be a very good idea under certain circumstances.
For the most part, you'll want to progress through the Campaign Tower only by using your free daily battles. However, during a Gem Event, you have a great opportunity to progress extremely far by spending Gems to bulk attack.
If you aren't familiar with what a bulk attack is, take a look at the Campaign Climbing Guide to learn more about how the Campaign Tower works as well as the best ways to progress through it.
However, progressing through the Campaign Tower isn't always the best option for completing the Gem Event. In some cases, it's definitely not a good idea at all!
You should only spend Gems to progress through the Campaign Tower if you satisfy some of the following conditions:
- You have not yet progressed very far in the Campaign Tower.
- You are not stuck in the Campaign Tower.
- You are also working on collecting seasonal currencies for a seasonal event.
If you've satisfied some of the above conditions, spending Gems to progress through the Campaign Tower using a 50x bulk attack can be a great idea. You will lose some Gems from your battles, but you will gain a ton of extra rewards as a result.
On top of that, you'll also start receiving much better daily rewards from the Campaign Tower.
The best time to progress through the Campaign Tower is during a seasonal event.
During a seasonal event, your primary goal is to collect as much of the seasonal currency as possible. The Campaign Tower just so happens to be an extremely good source of seasonal currencies!
If you ever happen to be working on completing a Gem Event and don't have much progress in the Campaign Tower, definitely think about progressing through the Campaign Tower to get some more Gems towards the completion of the Gem Event!