okay I think we go too far away from the main point, so maybe just answer my question:

Why should a new customer start a game where he know that from 510 existing cards 75 cards are unavailable for him but available for old players ?

I mean maybe somebody who have ambitions, want invest a lot of money and try to compete with the top-players for the leaderboard, before the lunch of this new reward cards it was possible he could buy or rent every card he want and play with full deck, now he can't.

So why he should under this circumstances play splinterlands and not just choice another game where new players has no disadvantages at the start (if they are ready to spent or invest money) ?

I mean it is not so that I am strong against soulbounded cards, it is okay in brawls and I could imagine to add a separate league where you can use this soulbounded cards BUT: It is not in this way, you can use this soulbounded cards in every ranked battle and in the most tournaments (at least when the tournaments are switched to sets what is only a question from some days).

I mean it is IMO clear, when you take part in a bike race you should come with a bike and not with your car, but it doesn't mean that their cannot be car races. So splinterlands could just create a third league where you can use this soulbounded cards, so that you could choice if you want play in a league with or without soulbounded cards.