The answer is in your first sentence. Makes no sense to discuss that at steam and 99% of the players are looking here anyway. Why to keep it in a sales platform?
Yes, but on Steam, 30% of the price goes to Valve (but you may consider they earned it because of the services they provide) and on TaleWorlds 100% of the price goes to TW.
As I understood it, the key is steam redeemable. So make it more sense to buy it here and then enter it in steam instead of buying it via steam directly?
Oh, and if I pay for early access. Do I need to pay later for the final release again?