Do you know the helping hand precent at level 80?
At the wikia page (
http://forgeofempires.wikia.com/wiki/Seed_Vault) it goes up to 20.
Lets try to run some math
Even if you get 1 full precent per 10 levels, it will bring you SV at level 80 to maximum of 10% chance for helping hands (and I would guess closer to 7%).
With 300 maximum friends/guilds/et cet you get 30 quests per day.
With 1% chance for diamonds, its like every 3-4 days to hit a 50 diamond. And quite easily once a week if you have less then that numbers.
Is that worth to you?