Thoughts and math about The Siren and The Avenger divination cards

Just want to share my thoughts about these two divination cards
The following assumptions and price checks refer to standard league.

The Avenger, 12 cards to get a corrupted Mjolner Gavel.
Cheapest price on poe.trade 1 exalted each card.
Cheapest clean mjolner with a buyout on poe.trade 10 exalted.
Vorici costs to get it with 3 linked sockets:
3 Jeweller Orbs, 3 Orb of Fusing, 6 Vaal

Corrupted mods that increase its value:
0.2% of Lightning Damage Leeched as Life
Gems in this item are supported by level 6 Stun
+(1 to 2) to Weapon range
Adds (8 to 11)-(19 to 23) Chaos Damage
White Sockets

The Siren, 7 cards to get a corrupted Whispering Ice Vile Staff
Cheapest price on poe.trade 10 chaos each card
Cheapest clean Whispering Ice on poe.trade 3 exalted
Vorici costs to get it with 6 sockets:
350 Jeweller Orbs, 350 Vaal Orb

Corrupted mods that increase its value:
White Sockets

Corrupted mods that are interesting but would disrupt the chance to block attacks:
0.2% of Cold Damage Leeched as Life
+1 Maximum Power Charge
(2 to 4)% Chance to Block Spells
Gems in this item are Supported by level 1 Increased Area of Effect

Estimated Exalted to Chaos Orb ratio 1:45
Estimated Exalted to Vaal Orb ratio 1:30
Estimated Exalted to Jeweller Orb ratio 1:210
Estimated Exalted to Orb of Fusing ratio 1:60

Conclusion

About buying the single cards: it is always not worth it in my opinion. Maybe if you only miss one card and you consider yourself RNG blessed.

About farming specific cards: I don't know how rare they are. Farming for currency in general, convert it into exalted orbs and then buy a clean item might be easier.

About balance: any card related to corrupted chests or corrupted two-hander weapons, is in my modest opinion a troll or a waste of money in supporter pack.