Benefit priority list
I recommend spending Benefit Material when all factions are available so that you can select the right characters For the current factions (Ally\Neutral), my priority is the usefulness of bonuses from Benefit Materials from highest to lowest:
1. Abraham - the character is used everywhere;
2. Sofia - stunning is cool
3. R.-high survival due to the shield;
4. Glenn is a great character that gives a bonus to survivability;
5. Dante - increased attack and defense for the entire battle, but the character is not always relevant in activities;
6. Rick Grimes - AOE;
7. Kate is a good character that will also increase survival;
8. Magna is a good character, the bonsu will make her even more useful.
9. Andea is the only damage dealer in the Ally.
The rest of the characters look less useful