Since it's been a couple days and people are finally receiving their S10 it looks like it's not available on all phones.
Basically in the USA and Canada if you got an unlocked S10 from the Samsung store, it doesn't have it installed.
If you got a Korean phone it should have it installed and if you got an T mobile branded locked USA phone it should have it installed.
You can check by going into security settings and there should be a Samsung blockchain option there.
Great observation and it looks like you want to have some Samsung Phone.
Well, this may vary from your country or what but I don't know the reason why its not available on all S10.
I doubt something that at this stage Samsung can accept cryptocurrency, in 2017 I heard that apple accepted cryptocurrency called xlm but still something did not work out)
Never heard about this thing, but let give more time for Samsung anyway this is just a cryptowallet not a coin or any form of investment so I think this will work well.