It specifically says in the event (here at least) that talisman souls don't count this time around... It's a shame as it was an easy way to complete the event but I can understand why they have made the decision to reign it in a bit (like the old saccathons...). I always had hundreds of Talisman souls to cash in and could complete the event without opening any normal souls at all, so I do like having to clear them out instead this time.