I don't think I could put same value on C1 miles as Sapphire point converted to CO miles as I use miles to redeem for business/first class tix between Asia and North America- thus value per mile is higher than if I used for Economy domestic tix. Unless the C1 points easily convert to international business class tix originating in Singapore. Am I correct in this assumption? I will go for a C1 when/if they bring back a mileage matching promotion or similar.

Looks like I should stick to my Chase for now. An AMEX Plat might be nice but we typically fly business everywhere so little value for lounge access. Are the points earned through AMEX "better" than Chase points if converting to CO or AA miles in terms of higher Conversion ratio?