If you have a decent team from the captain event you can take three players to improve your squad. I think it's more than enough. If you also took three from the Ragnarok event you allready have half a team.
That doesn't even come close to (for example) the Euros event last year where I built the best squad possible using only tradable cards, compared to the current captains event where I only got one card (Marquez) and have 1200 shards barely for a great card, I can definitely say it's a lot more difficult to upgrade my squad.
The market is useless now because most of the cards are untradable and because the players we got are better than the one on the market
That is partially correct but the main reason is that the coins rewards are heavily disproportionate with the inflated market. You can barely make 20M coins a day from rewards while a half decent card costs 1B coins.