Greetings hero! This event is primarily aimed at new players so that they can upgrade themselves up and get new rewards. The second event, designed for all players with interesting quests, is coming soon.
This is the first time I've heard of an event designed to be harder for older players. Logically it appears that players are punished for playing the game a lot. Personally, as a completionist, by being blocked from completing this event I no longer find the game worth my time.
Another matter that should be addressed is the ridiculous healing rates of AI, especially in the tower, where 3-5 thousand HP restored in a single move is common while players are healed for much less. There's no challenge in the fights themselves, they just take forever to finish, which for a 'match 3' game isn't really that great.